Synthesis of 1-(2,2-Dimethylpropyl)-Cyclopropene (1-DCP) as an Ethylene Antagonist.

Ethylene is a gaseous hydrocarbon molecule known as a plant hormone that promotes fruit ripening and senescence. Efficiently controlling ethylene is a central key to maintaining the quality of agricultural products. The current study uncovered a synthetic method for 1-(2,2-dimethylpropyl)-cyclopropene (1-DCP) as a cyclopropene derivative to inhibit ethylene action in fruit ripening and senescence. We synthesized 1-DCP using α-diisobutylene through a two-step process, including allylic chlorination by hypochlorite and HCl, followed by α-elimination of the allylic chloride using a strong base, lithium diethylamide. GC-MS and NMR analyses demonstrated that 1-DCP was synthesized efficiently with 35% yield and 95% purity. When treated as an aqueous emulsion on plants, including persimmon and banana fruits, 1 mM 1-DCP showed effective inhibition of ethylene action by delaying the flesh softening and peel degreening, which are representative phenomena of fruit ripening and senescence induced by ethylene. Our data demonstrated that 1-DCP could be synthesized and used as a sprayable ethylene antagonist for pre- or post-harvest growth regulation in plants and fruits.

Anti-Atherosclerosis and Anti-Hyperlipidemia Functions of Terminalia catappa Fruit.

Background: Atherosclerosis is a chronic pathological condition that has remained clinically silent for decades, and the epidemic has continued to be on the rise due to risk factors, including diet, lifestyle, hyperlipidemia, pathogenic microorganisms, and aging. Using various synthetic drugs in treating atherosclerosis is associated with a high risk of myositis, angioedema, myoglobinuria, and acute renal failure. Various side effects of the available drugs have been reported; attempts are underway to explore natural sources with antiatherosclerotic activity. Aim and objective: Using a diet-induced atherosclerosis rat model, the current study tested the hypothesis of antiatherosclerotic and antihyperlipidemic roles of Terminalia catappa fruit extracts. Materials and Methods: Atherosclerosis in Wistar rats was induced using an atherogenic diet. Total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (AP), creatine kinase (CK), and lactate dehydrogenase (LDH) were determined using analytical kits. Results: Quantitative phytochemical analysis of the extracts demonstrated that the plant had flavonoids, saponins, tannins, terpenoids, alkaloids, cardiac glycosides, sterols, phenols, and anthraquinones. Diet-induced atherogenic Wistar rats showed a significant (p < 0.05) increase in total cholesterol, triglyceride, low-density lipoprotein cholesterol, and very low-density lipoprotein cholesterol compared to the healthy control group; however, the atherogenic lipid profile was reversed by the treatment of T. catappa fruit extracts. The biochemical experiments demonstrate that T. catappa fruit extracts have an antihyperlipidaemic effect, shown by a decreased coronary risk index and the atherogenic index, and an increased cardioprotective index, compared to disease control. Conclusion: The current study indicates that T. catappa fruit extracts may contain bioactive molecules to treat atherosclerosis.

Mitochondrial-nuclear communication by prohibitin shuttling under oxidative stress.

Mitochondrial-nuclear communication is critical for maintaining mitochondrial activity under stress conditions. Adaptation of the mitochondrial-nuclear network to changes in the intracellular oxidation and reduction milieu is critical for the survival of retinal and retinal pigment epithelial (RPE) cells, in relation to their high oxygen demand and rapid metabolism. However, the generation and transmission of the mitochondrial signal to the nucleus remain elusive. Previously, our in vivo study revealed that prohibitin is upregulated in the retina, but downregulated in RPE cells in the aging and diabetic model. In this study, the functional role of prohibitin in the retina and RPE cells was examined using biochemical methods, including a lipid binding assay, two-dimensional gel electrophoresis, immunocytochemistry, Western blotting, and a knockdown approach. Protein depletion by siRNA characterized prohibitin as an anti-apoptotic molecule in mitochondria, while the lipid binding assay demonstrated subcellular communication between mitochondria and the nucleus under oxidative stress. The changes in the expression and localization of mitochondrial prohibitin triggered by reactive oxygen species are crucial for mitochondrial integrity. We propose that prohibitin shuttles between mitochondria and the nucleus as an anti-apoptotic molecule and a transcriptional regulator in a stress environment in the retina and RPE cells.

Viral mimicry of Cdc2/cyclin-dependent kinase 1 mediates disruption of nuclear lamina during human cytomegalovirus nuclear egress.

The nuclear lamina is a major obstacle encountered by herpesvirus nucleocapsids in their passage from the nucleus to the cytoplasm (nuclear egress). We found that the human cytomegalovirus (HCMV)-encoded protein kinase UL97, which is required for efficient nuclear egress, phosphorylates the nuclear lamina component lamin A/C in vitro on sites targeted by Cdc2/cyclin-dependent kinase 1, the enzyme that is responsible for breaking down the nuclear lamina during mitosis. Quantitative mass spectrometry analyses, comparing lamin A/C isolated from cells infected with viruses either expressing or lacking UL97 activity, revealed UL97-dependent phosphorylation of lamin A/C on the serine at residue 22 (Ser(22)). Transient treatment of HCMV-infected cells with maribavir, an inhibitor of UL97 kinase activity, reduced lamin A/C phosphorylation by approximately 50%, consistent with UL97 directly phosphorylating lamin A/C during HCMV replication. Phosphorylation of lamin A/C during viral replication was accompanied by changes in the shape of the nucleus, as well as thinning, invaginations, and discrete breaks in the nuclear lamina, all of which required UL97 activity. As Ser(22) is a phosphorylation site of particularly strong relevance for lamin A/C disassembly, our data support a model wherein viral mimicry of a mitotic host cell kinase activity promotes nuclear egress while accommodating viral arrest of the cell cycle.

Fatty Acid Composition and Stoichiometry Determine the Angiogenesis Microenvironment.

The current study tested the hypothesis of whether specific lipids may control angiogenic reactions. Using the chorioallantoic membrane assay of the chick embryo, new vessel formation was analyzed quantitatively by gas chromatography and mass spectrometry as well as bioinformatics tools including an angiogenesis analyzer. Our biochemical experiments showed that a specific lipid composition and stoichiometry determine the angiogenesis microenvironment to accelerate or inhibit vessel formation. Specific lipids of angiogenesis determinants in the vessel area and the non-vessel area were identified as nitrooleic acid, docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), palmitic acid, oleic acid, linoleic acid, linolenic acid, epoxyoleic acid, lysophosphatidylcholine (LPC), cholesterol, 7-ketocholesterol, and docosahexaenoyl lysophosphatidylcholine (DHA-LPC). Vessel formation happens on the surface area of the hydrophilic membrane of the yolk. Our biochemical data demonstrated that angiogenesis was followed in the white lipid complex area to generate more branches, junctions, segments, and extremities. We analyzed lipid fragments in the vessel, non-vessel, and albumen area to show that each area contains a specific lipid composition and stoichiometry. Mass spectrometry data demonstrated that the vessel area has higher concentrations of nitrooleic acid, palmitic acid, stearic acid, LPC, lysophosphatidylethanolamine, cholesterol, oleic acid, linoleic acid, 7-ketocholesterol, and DHA-LPC; however, DHA and EPA were abundant in the hydrophobic non-vessel area. The purpose of vessel formation is to wrap up the yolk area to transport nutrients including specific fatty acids. Besides, angiogenesis requires aqueous albumen shown by distance-dependent vessel formation from albumen and oxygen. Higher concentrations of fatty acids are required for energy and carbon structure from the carbon-carbon bond, membrane building blocks, and amphiphilic detergent to solubilize a hydrophobic environment in the aqueous blood layer. The current study may guide that the uncovered hydrophobic or zwitterionic molecules such as DHA and DHA-LPC may control angiogenesis as antiangiogenic or proangiogenic molecules as potential drug targets for treating uncontrolled angiogenesis-related diseases, including diabetic retinopathy and age-related macular degeneration.

Role of Rho-kinase in regulation of insulin action and glucose homeostasis.

Accumulating evidence indicates an important role for serine phosphorylation of IRS-1 in the regulation of insulin action. Recent studies suggest that Rho-kinase (ROK) is a mediator of insulin signaling, via interaction with IRS-1. Here we show that insulin stimulation of glucose transport is impaired when ROK is chemically or biologically inhibited in cultured adipocytes and myotubes and in isolated soleus muscle ex vivo. Inactivation of ROK also reduces insulin-stimulated IRS-1 tyrosine phosphorylation and PI3K activity. Moreover, inhibition of ROK activity in mice causes insulin resistance by reducing insulin-stimulated glucose uptake in skeletal muscle in vivo. Mass spectrometry analysis identifies IRS-1 Ser632/635 as substrates of ROK in vitro, and mutation of these sites inhibits insulin signaling. These results strongly suggest that ROK regulates insulin-stimulated glucose transport in vitro and in vivo. Thus, ROK is an important regulator of insulin signaling and glucose metabolism.

Characterization of a chromosomal toxin-antitoxin, Rv1102c-Rv1103c system in Mycobacterium tuberculosis.

Toxin-antitoxin systems, ubiquitous in prokaryotic genomes, have been proposed to play an important role in several stress responses. While Mycobacterium tuberculosis contains more than 80 putative TA loci, the roles they play in this pathogen are yet to be studied. Here, we characterize a chromosomal Rv1102c-Rv1103c TA system in M. tuberculosis. We found that the Rv1102c toxin interacts with the Rv1103c antitoxin in a pull-down assay and the yeast two-hybrid system. Rv1102c cleaved the era mRNA in Escherichia coli, and cleavage was inhibited by co-expression of Rv1103c. Heterologous expression of Rv1102c led to growth arrest in E. coli, which was fully recovered only when Rv1103c was co-expressed in cis with Rv1102c, suggesting that the production and assembly of Rv1102c and Rv1103c are tightly linked. Our additional results indicate that translational coupling of the Rv1102c and Rv1103c genes is important for Rv1102c-Rv1103c binding. Finally, we discovered that the expression of Rv1102c induced growth arrest and increased the level of persister cells in Mycobacterium smegmatis. These results suggest that the Rv1102c-Rv1103c TA system could play a role in M. tuberculosis pathogenesis via generating bacilli that survive in the face of multidrug therapy.

Association of Age-Related Macular Degeneration on Alzheimer or Parkinson Disease: A Retrospective Cohort Study.

PURPOSE: To determine the association of age-related macular degeneration (AMD) with Alzheimer disease (AD) and Parkinson disease (PD). DESIGN: Retrospective cohort study. METHODS: The study population consisted of 308,340 participants aged 50 years or older from the Korean National Health Insurance Service-Health Screening Cohort. After exclusion of participants with AMD during 2002, participants were detected for AMD during 2003-2005. Starting from January 1, 2006, all participants were followed up for AD and PD until December 31, 2013. Multivariate Cox proportional hazards regression was used to calculate the adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for AD and PD risk. RESULTS: Compared to non-AMD participants, AMD patients had higher risk for AD (aHR 1.48, 95% CI 1.25-1.74) and PD (aHR 1.46, 95% CI 1.14-1.88). The risk-increasing association of AMD with AD (aHR 2.25, 95% CI 1.39-3.66) and PD (aHR 2.02, 95% CI 1.00-4.08) were preserved among participants who were never-smokers, did not consume alcohol, and exercised regularly. Finally, AMD was associated with higher risk of AD (aHR 1.96, 95% CI 1.46-2.65 for age <70 years and aHR 1.53, 95% CI 1.26-1.86 for age ≥70 years) and PD (aHR 1.90, 95% CI 1.29-2.80 for age <70 years and aHR 1.47, 95% CI 1.06-2.04 for age ≥70 years) according to subgroups divided by age. CONCLUSIONS: Compared to non-AMD participants, AMD patients had higher risk for AD and PD even among those with healthy lifestyle behaviors. Patients with AMD must be closely monitored for possible subsequent development of AD or PD.

Anti-diabetic effects of Ficus Asperifolia in Streptozotocin-induced diabetic rats.

PURPOSE: The current study aimed to determine the antidiabetic effects of leaf extract of Ficus asperifolia in streptozotocin-induced diabetic rats. METHODS: A total of ninety-five (95) adult rats were used for the experiment. The whole study protocol was divided into three sets of individual experiments. The animals were divided randomly into seven groups of five rats each. The rats were given a diet supplemented with 50 g high fat to 50 g vital feeds for two weeks. The study lasted 28 days with daily administration and weekly blood glucose and body weight check. At the end of the experiment protocol, the rats were fasted overnight and were anesthetized. Blood was collected via cardiac puncture from each animal for biochemical analysis. Metglim 3.38 mg/kg bodyweight was used as positive control. Diabetes was induced using streptozotocin (35 mg/kg in 0.1 M phosphate-buffered saline) intraperitoneally for 5 days. Phytochemicals were analyzed in both extract and fractions. RESULTS: Phytochemical screening revealed the presence of alkaloids, saponins, flavonoids, glycosides, tannins, carotenoids, terpenes, and steroids in both extract and fractions. Proteins, carbohydrates, and fats were detected by systematic molecular analysis. Fraction 1 of plant extracts prevented glucose-induced hyperglycaemia 30 min' post glucose load in all rats. Streptozotocin treatment caused a significant increase (p˂0.05) in blood sugar, total cholesterol, triacylglycerol, low-density lipoproteins and a significant (p˂0.05) decrease in food intake, body weight and high-density lipoproteins in diabetic rats. CONCLUSION: Treatment with the extract significantly improved the derangements caused by streptozotocin. These results suggest that the leaf extracts of Ficus asperifolia could serve as a potential treatment for diabetes therapy.

Correction to: Anti-diabetic effects of Ficus Asperifolia in Streptozotocin-induced diabetic rats.

[This corrects the article DOI: 10.1007/s40200-020-00524-1.].

Age- and sex-based evaluation of the association between refractive error and age-related macular degeneration in the Korean population.

PURPOSE: The aim of this study was to investigate the association between refractive error and prevalence of age-related macular degeneration (AMD) in Korean adults, based on the sex and age group. METHODS: This was a nationwide population-based cross-sectional study that included 17,676 subjects aged over 40 years who participated in the 2008-2012 Korean National Health and Nutrition Examination Survey. Digital fundus images (45°) were obtained for both eyes under physiologic mydriasis and were graded using the international classification and grading system for age-related macular degeneration. The spherical equivalents of refractive errors were calculated in diopters using auto-refraction data. RESULTS: After adjustment for potential confounders, myopia was associated with lower risk of any age-related macular degeneration [odds ratio (OR), 0.74; 95% Confidence Interval (CI), 0.61-0.91]. In particular, myopia was significantly associated with lower odds of age-related macular degeneration in female participants (any AMD: OR, 0.71; 95% CI, 0.54-0.93; early AMD: OR, 0.70; 95% CI, 0.53-0.93) and in participants younger than 50 years (any AMD: OR, 0.46; 95% CI, 0.24-0.90; early AMD: OR, 0.47; 95% CI, 0.24-0.93). There was no significant association between myopia and age-related macular degeneration in male participants and in participants older than 50 years. CONCLUSIONS: In the Korean adult population, myopia was associated with significantly lower odds of any type of early age-related macular degeneration, particularly in females and in younger age groups.

Dual Switch Mechanism of Erythropoietin as an Antiapoptotic and Pro-Angiogenic Determinant in the Retina.

Constant or intense light degenerates the retina and retinal pigment epithelial cells. Light generates reactive oxygen species and nitric oxide leading to initial reactions of retinal degeneration. Apoptosis is the primary mechanism of abnormal death of photoreceptors, retinal ganglion cells, or retinal pigment epithelium (RPE) in degenerative retinal diseases, including diabetic retinopathy and age-related macular degeneration. The current study evaluated the function of erythropoietin (EPO) on angiogenesis and apoptosis in the retina and RPE under oxidative stress. We determined the pro-angiogenic and antiapoptotic mechanism of EPO under stress conditions using a conditional EPO knockdown model using siRNA, EPO addition, proteomics, immunocytochemistry, and bioinformatic analysis. Our studies verified that EPO protected retinal cells from light-, hypoxia-, hyperoxia-, and hydrogen peroxide-induced apoptosis through caspase inhibition, whereas up-regulated angiogenic reactions through vascular endothelial growth factor (VEGF) and angiotensin pathway. We demonstrated that the EPO expression in the retina and subsequent serine/threonine/tyrosine kinase phosphorylations might be linked to oxidative stress response tightly to determining angiogenesis and apoptosis. Neuroprotective roles of EPO may involve the balance between antiapoptotic and pro-angiogenic signaling molecules, including BCL-xL, c-FOS, caspase-3, nitric oxide, angiotensin, and VEGF receptor. Our data indicate a new therapeutic application of EPO toward retinal degeneration based on the dual roles in apoptosis and angiogenesis at the molecular level under oxidative stress.

Mechanistic dissection of diabetic retinopathy using the protein-metabolite interactome.

PURPOSE: The current study aims to determine the molecular mechanisms of diabetic retinopathy (DR) using the protein-protein interactome and metabolome map. We examined the protein network of novel biomarkers of DR for direct (physical) and indirect (functional) interactions using clinical target proteins in different models. METHODS: We used proteomic tools including 2-dimensional gel electrophoresis, mass spectrometry analysis, and database search for biomarker identification using in vivo murine and human model of diabetic retinopathy and in vitro model of oxidative stress. For the protein interactome and metabolome mapping, various bioinformatic tools that include STRING and OmicsNet were used. RESULTS: We uncovered new diabetic biomarkers including prohibitin (PHB), dynamin 1, microtubule-actin crosslinking factor 1, Toll-like receptor (TLR 7), complement activation, as well as hypothetical proteins that include a disintegrin and metalloproteinase (ADAM18), vimentin III, and calcium-binding C2 domain-containing phospholipid-binding switch (CAC2PBS) using a proteomic approach. Proteome networks of protein interactions with diabetic biomarkers were established using known DR-related proteome data. DR metabolites were interconnected to establish the metabolome map. Our results showed that mitochondrial protein interactions were changed during hyperglycemic conditions in the streptozotocin-treated murine model and diabetic human tissue. CONCLUSIONS: Our interactome mapping suggests that mitochondrial dysfunction could be tightly linked to various phases of DR pathogenesis including altered visual cycle, cytoskeletal remodeling, altered lipid concentration, inflammation, PHB depletion, tubulin phosphorylation, and altered energy metabolism. The protein-metabolite interactions in the current network demonstrate the etiology of retinal degeneration and suggest the potential therapeutic approach to treat DR.

Role of Endothelial ADAM17 in Early Vascular Changes Associated with Diabetic Retinopathy.

ADAM17, a disintegrin and metalloproteinase 17, is a transmembrane metalloproteinase that regulates bioavailability of multiple membrane-bound proteins via ectodomain shedding. ADAM17 activity was shown to contribute to a number of vascular pathologies, but its role in the context of diabetic retinopathy (DR) is not determined. We found that expression and enzymatic activity of ADAM17 are upregulated in human diabetic postmortem retinas and a mouse model of streptozotocin-induced diabetes. To further investigate the contribution of ADAM17 to vascular alterations associated with DR, we used human retinal endothelial cells (HREC) treated with ADAM17 neutralizing antibodies and exposed to glucidic stress and streptozotocin-induced endothelial ADAM17 knockout mice. Evaluation of vascular permeability, vascular inflammation, and oxidative stress was performed. Loss of ADAM17 in endothelial cells markedly reduced oxidative stress evidenced by decreased levels of superoxide, 3-nitrotyrosine, and 4-hydroxynonenal and decreased leukocyte-endothelium adhesive interactions in vivo and in vitro. Reduced leukostasis was associated with decreased vascular permeability and was accompanied by downregulation of intercellular adhesion molecule-1 expression. Reduction in oxidative stress in HREC was associated with downregulation of NAD(P)H oxidase 4 (Nox4) expression. Our data suggest a role for endothelial ADAM17 in DR pathogenesis and identify ADAM17 as a potential new therapeutic target for DR.

Oleic Acid, Cholesterol, and Linoleic Acid as Angiogenesis Initiators.

The current study determined the natural angiogenic molecules using an unbiased metabolomics approach. A chick chorioallantoic membrane (CAM) model was used to examine pro- and antiangiogenic molecules, followed by gas chromatography-mass spectrometry (GCMS) analysis. Vessel formation was analyzed quantitatively using the angiogenic index (p < 0.05). At embryonic day one, a white streak or circle area was observed when vessel formation begins. GCMS analysis and database search demonstrated that angiogenesis may initiate when oleic, cholesterol, and linoleic acids increased in the area of angiogenic reactions. The gain of function study was conducted by the injection of cholesterol and oleic acid into a chick embryo to determine the role of each lipid in angiogenesis. We propose that oleic acid, cholesterol, and linoleic acid are natural molecules that set the platform for the initiation stage of angiogenesis before other proteins including the vascular endothelial growth factor, angiopoietin, angiotensin, and erythropoietin join as the angiome in sprout extension and vessel maturation.

Neuroprotective role of erythropoietin by antiapoptosis in the retina.

Erythropoietin (EPO) stimulates red blood cell production, in part by inhibiting apoptosis of the red blood cell precursors. The erythropoietic effects of EPO are circadian stage dependent. Retinal injury due to light occurs through oxidative mechanisms and is manifest by retinal and retinal pigment epithelium (RPE) cells apoptosis. The visual cycle might be circadian coordinated as a means of effectively protecting the retina from the detrimental effects of light-induced, oxygen-dependent, free radical-mediated damage, especially at the times of day when light is more intense. We show that the retinal expression of EPO and its receptor (EPOR), as well as subsequent Janus kinase 2 (Jak2) phosphorylations, are each tightly linked to a specific time after oxidative stress and in anticipation of daily light onset. This is consistent with physiological protection against daily light-induced, oxidatively mediated retinal apoptosis. In vitro, we verify that EPO protects RPE cells from light, hyperoxia, and hydrogen peroxide-induced retinal cell apoptosis, and that these stimuli increase EPO and EPOR expression in cultured RPE cells. Together, these data support the premise that EPO and its EPOR interactions represent an important retinal shield from physiologic and pathologic light-induced oxidative injury.

The phosphoinositide kinase PIKfyve mediates epidermal growth factor receptor trafficking to the nucleus.

ErbB receptor tyrosine kinases can transit to nuclei in tumor cells, where they have been shown to regulate gene expression as components of transcriptional complexes. Quantitative analysis of a human bladder cancer tissue microarray identified nuclear epidermal growth factor receptor (EGFR) in tumor cells and also showed an increased frequency of this histologic feature in cancer relative to normal tissues. This observation suggests a potential role for nuclear EGFR in bladder cancer. We confirmed that EGFR could be induced to transit to nuclei in cultured human bladder cancer cells in response to the urothelial cell growth factor and EGFR ligand heparin-binding EGF-like growth factor (HB-EGF). Mass spectrometric analysis of EGFR immune complexes from a transitional carcinoma cell line (TCCSUP) identified the phosphoinositide kinase, PIKfyve, as a potential component of the EGFR trafficking mechanism. RNA silencing indicated that PIKfyve is a mediator of HB-EGF-stimulated EGFR nuclear trafficking, EGFR binding to the cyclin D1 promoter, and cell cycle progression. These results identify a novel mediator of the EGFR transcription function and further suggest that nuclear EGFR and the lipid kinase PIKfyve may play a role in bladder oncogenesis.

Melatonin Modulates Prohibitin and Cytoskeleton in the Retinal Pigment Epithelium.

The retinal pigment epithelium (RPE) plays imperative roles in normal retinal function by photoreceptor protection from light and phagocytosis of rod and cone outer segments during disc shedding. Melatonin is the free radical scavenger and circadian determinant to protect the RPE and retina from oxidative stress and regulate the circadian clock. The current study tested the hypothesis whether melatonin could affect cytoskeletal structure within RPE. Our Western blot analysis demonstrated that melatonin treatment up-regulated prohibitin 3-fold compared to control. ß-tubulin levels were also up-regulated by melatonin but to a lesser extent. Initial cell shape of ARPE-19 is epitheloid, however, after 30-minute treatment with melatonin, RPE cells undergo a morphological change to a fusiform shape with spindle outgrowth. Cells return to epitheloid shape after 12 hours in untreated medium. Melatonin treated cells showed increased and dissimilar distribution of prohibitin and ß-tubulin compared to non-treated cells, thus altered cytoskeletal and mitochondrial structure in the RPE. Our data implies that melatonin may play a protective role under oxidative stress, which is shown by the marker prohibitin in terms of increased expression and nuclear distribution. During the protective process, cells change their morphology. Our results suggest that melatonin treatment could be beneficial to protect mitochondria under oxidative stress and treat certain ocular diseases, including age-related macular degeneration.

Disruption of Angiogenesis by Anthocyanin-Rich Extracts of Hibiscus sabdariffa.

Abnormal vessel formations contribute to the progression of specific angiogenic diseases including age-related macular degeneration. Adequate vessel growth and maintenance represent the coordinated process of endothelial cell proliferation, matrix remodeling, and differentiation. However, the molecular mechanism of the proper balance between angiogenic activators and inhibitors remains elusive. In addition, quantitative analysis of vessel formation has been challenging due to complex angiogenic morphology. We hypothesized that conjugated double bond containing-natural products, including anthocyanin extracts from Hibiscus sabdariffa, may control the proper angiogenesis. The current study was designed to determine whether natural molecules from African plant library modulate angiogenesis. Further, we questioned how the proper balance of anti- or pro-angiogenic signaling can be obtained in the vascular microenvironment by treating anthocyanin or fatty acids using chick chorioallantoic membrane angiogenesis model in ovo. The angiogenic morphology was analyzed systematically by measuring twenty one angiogenic indexes using Angiogenic Analyzer software. Chick chorioallantoic model demonstrated that anthocyanin-rich extracts inhibited angiogenesis in time- and concentration-dependent manner. Molecular modeling analysis proposed that hibiscetin as a component in Hibiscus may bind to the active site of vascular endothelial growth factor receptor 2 (VEGFR2) with ΔG= -8.42 kcal/mol of binding energy. Our results provided the evidence that anthocyanin is an angiogenic modulator that can be used to treat uncontrolled neovascular-related diseases, including age-related macular degeneration.

Interactome Mapping Guided by Tissue-Specific Phosphorylation in Age-Related Macular Degeneration.

The current study aims to determine the molecular mechanisms of age-related macular degeneration (AMD) using the phosphorylation network. Specifically, we examined novel biomarkers for oxidative stress by protein interaction mapping using in vitro and in vivo models that mimic the complex and progressive characteristics of AMD. We hypothesized that the early apoptotic reactions could be initiated by protein phosphorylation in region-dependent (peripheral retina vs. macular) and tissue-dependent (retinal pigment epithelium vs. retina) manner under chronic oxidative stress. The analysis of protein interactome and oxidative biomarkers showed the presence of tissue- and region-specific post-translational mechanisms that contribute to AMD progression and suggested new therapeutic targets that include ubiquitin, erythropoietin, vitronectin, MMP2, crystalline, nitric oxide, and prohibitin. Phosphorylation of specific target proteins in RPE cells is a central regulatory mechanism as a survival tool under chronic oxidative imbalance. The current interactome map demonstrates a positive correlation between oxidative stress-mediated phosphorylation and AMD progression and provides a basis for understanding oxidative stress-induced cytoskeletal changes and the mechanism of aggregate formation induced by protein phosphorylation. This information could provide an effective therapeutic approach to treat age-related neurodegeneration.