Crosstalk between the DNA damage response and cellular senescence drives aging and age-related diseases.

Cellular senescence is a crucial process of irreversible cell-cycle arrest, in which cells remain alive, but permanently unable to proliferate in response to distinct types of stressors. Accumulating evidence suggests that DNA damage builds over time and triggers DNA damage response signaling, leading to cellular senescence. Cellular senescence serves as a platform for the perpetuation of inflammatory responses and is central to numerous age-related diseases.

CD40 Ligand-CD40 Interaction Is an Intermediary between Inflammation and Angiogenesis in Proliferative Diabetic Retinopathy.

We aimed to investigate the role of the CD40-CD40 ligand (CD40L) pathway in inflammation-mediated angiogenesis in proliferative diabetic retinopathy (PDR). We analyzed vitreous fluids and epiretinal fibrovascular membranes from PDR and nondiabetic patients, cultures of human retinal microvascular endothelial cells (HRMECs) and Müller glial cells and rat retinas with ELISA, immunohistochemistry, flow cytometry and Western blot analysis. Functional tests included measurement of blood-retinal barrier breakdown, in vitro angiogenesis and assessment of monocyte-HRMEC adherence.

Molecular mechanism of VEGF and its role in pathological angiogenesis.

Over the last seven decades, a significant scientific contribution took place in the delineation of the implications of vascular endothelial-derived growth factor (VEGF) in the processes of angiogenesis. Under pathological conditions, mainly in response to hypoxia or ischemia, elevated VEGF levels promote vascular damage and the growth of abnormal blood vessels. Indeed, the development of VEGF biology has revolutionized our understanding of its role in pathological conditions.

Differential Expression and Localization of ADAMTS Proteinases in Proliferative Diabetic Retinopathy.

We analyzed the expression of ADAMTS proteinases ADAMTS-1, -2, -4, -5 and -13; their activating enzyme MMP-15; and the degradation products of proteoglycan substrates versican and biglycan in an ocular microenvironment of proliferative diabetic retinopathy (PDR) patients. Vitreous samples from PDR and nondiabetic patients, epiretinal fibrovascular membranes from PDR patients, rat retinas, retinal Müller glial cells and human retinal microvascular endothelial cells (HRMECs) were studied. The levels of ADAMTS proteinases and MMP-15 were increased in the vitreous from PDR patients.

Proprotein convertase furin is a driver and potential therapeutic target in proliferative diabetic retinopathy.

Background: Furin converts inactive proproteins into bioactive forms. By activating proinflammatory and proangiogenic factors, furin might play a role in pathophysiology of proliferative diabetic retinopathy (PDR).

Methods: We studied vitreous samples from PDR and nondiabetic patients, epiretinal membranes from PDR patients, retinal microvascular endothelial cells (HRMECs), retinal Müller cells and rat retinas by ELISA, Western blot analysis, immunohistochemistry and immunofluorescence microscopy.

Tissue Inhibitor of Metalloproteinase-3 Ameliorates Diabetes-Induced Retinal Inflammation.

Endogenous tissue inhibitor of matrix metalloproteinase-3 (TIMP-3) has powerful regulatory effects on inflammation and angiogenesis. In this study, we investigated the role of TIMP-3 in regulating inflammation in the diabetic retina. Vitreous samples from patients with proliferative diabetic retinopathy (PDR) and non-diabetic patients were subjected to Western blot analysis.

Flavonoids and PI3K/Akt/mTOR Signaling Cascade: A Potential Crosstalk in Anticancer Treatment.

Cancer is one of the leading causes of death worldwide. A slight decline in mortality has been noted, but the currently available treatment options did not give an expected outcome and are associated with several side effects resulting a substantial economic burden. The advent of plant-based treatment is rising because of its ease of use, ready availability, cost-effectiveness, and low/no toxicity.

CD146/Soluble CD146 Pathway Is a Novel Biomarker of Angiogenesis and Inflammation in Proliferative Diabetic Retinopathy.

Purpose: Inflammation, angiogenesis and fibrosis are pathological hallmarks of proliferative diabetic retinopathy (PDR). The CD146/sCD146 pathway displays proinflammatory and proangiogenic properties. We investigated the role of this pathway in the pathophysiology of PDR.

Evaluation of Proteoforms of the Transmembrane Chemokines CXCL16 and CX3CL1, Their Receptors, and Their Processing Metalloproteinases ADAM10 and ADAM17 in Proliferative Diabetic Retinopathy.

The transmembrane chemokine pathways CXCL16/CXCR6 and CX3CL1/CX3CR1 are strongly implicated in inflammation and angiogenesis. We investigated the involvement of these chemokine pathways and their processing metalloproteinases ADAM10 and ADAM17 in the pathophysiology of proliferative diabetic retinopathy (PDR). Vitreous samples from 32 PDR and 24 non-diabetic patients, epiretinal membranes from 18 patients with PDR, rat retinas, human retinal Müller glial cells and human retinal microvascular endothelial cells (HRMECs) were studied by enzyme-linked immunosorbent assay, immunohistochemistry and Western blot analysis.

Apocynin ameliorates NADPH oxidase 4 (NOX4) induced oxidative damage in the hypoxic human retinal Müller cells and diabetic rat retina.

NADPH oxidase (NOX) is a main producers of reactive oxygen species (ROS) that may contribute to the early pathogenesis of diabetic retinopathy (DR). ROS has harmful effects on endogenous neuro-survival factors brain-derived neurotrophic factor (BDNF) and sirtuin 1 (SIRT1) are necessary for the growth and survival of the retina. The role of NOX isoforms NOX4 in triggering ROS in DR is not clear.

The Role of Neurovascular System in Neurodegenerative Diseases.

The neurovascular system (NVS), which consisted of neurons, glia, and vascular cells, is a functional and structural unit of the brain. The NVS regulates blood-brain barrier (BBB) permeability and cerebral blood flow (CBF), thereby maintaining the brain's microenvironment for normal functioning, neuronal survival, and information processing. Recent studies have highlighted the role of vascular dysfunction in several neurodegenerative diseases.

The Proinflammatory and Proangiogenic Macrophage Migration Inhibitory Factor Is a Potential Regulator in Proliferative Diabetic Retinopathy.

The macrophage migration inhibitory factor (MIF)/CD74 signaling pathway is strongly implicated in inflammation and angiogenesis. We investigated the expression of MIF and its receptor CD74 in proliferative diabetic retinopathy (PDR) to reveal a possible role of this pathway in the pathogenesis of PDR. Levels of MIF, soluble (s)CD74, soluble intercellular adhesion molecule-1 (sICAM-1) and vascular endothelial growth factor (VEGF) were significantly increased in the vitreous from patients with PDR compared to nondiabetic control samples.

Interleukin-11 Overexpression and M2 Macrophage Density are Associated with Angiogenic Activity in Proliferative Diabetic Retinopathy.

Purpose: To investigate the expression of IL-11 and its receptor IL-11Rα and to quantify density of CD163 M2 macrophages in proliferative diabetic retinopathy (PDR).

Methods: Vitreous samples from 29 PDR and 19 nondiabetic patients, epiretinal fibrovascular membranes from 15 patients with PDR and Müller cells were studied by enzyme-linked immunosorbent assay, immunohistochemistry and Western blot analysis.

Results: We showed a significant increase in expression of IL-11, soluble(s) IL-11Rα, sCD163 and VEGF in vitreous samples from PDR patients compared to nondiabetic controls.

Galectin-1 studies in proliferative diabetic retinopathy.

Purpose: Galectin-1 regulates endothelial cell function and promotes angiogenesis. We investigated the hypothesis that galectin-1 may be involved in the pathogenesis of proliferative diabetic retinopathy (PDR).

Methods: Vitreous samples from 36 PDR and 20 nondiabetic patients, epiretinal fibrovascular membranes from 13 patients with PDR, rat retinas and human retinal Müller glial cells were studied by enzyme-linked immunosorbent assay (ELISA), immunohistochemistry and Western blot analysis.

Cross-Talk between Sirtuin 1 and the Proinflammatory Mediator High-Mobility Group Box-1 in the Regulation of Blood-Retinal Barrier Breakdown in Diabetic Retinopathy.

: High-mobility group box-1 (HMGB1) mediates inflammation and breakdown of blood-retinal barrier (BRB) in diabetic retina. Sirtuin-1 (SIRT1) has protective effects against inflammation and oxidative stress. The aim of this study was to investigate the interaction between HMGB1 and SIRT1 in regulating BRB breakdown in diabetic retina.

AKAP1 Protects from Cerebral Ischemic Stroke by Inhibiting Drp1-Dependent Mitochondrial Fission.

Mitochondrial fission and fusion impact numerous cellular functions and neurons are particularly sensitive to perturbations in mitochondrial dynamics. Here we describe that male mice lacking the mitochondrial A-kinase anchoring protein 1 (AKAP1) exhibit increased sensitivity in the transient middle cerebral artery occlusion model of focal ischemia. At the ultrastructural level, AKAP1 mice have smaller mitochondria and increased contacts between mitochondria and the endoplasmic reticulum in the brain.

Matrix metalloproteinase-14 is a biomarker of angiogenic activity in proliferative diabetic retinopathy.

Purpose: Matrix metalloproteinase-14 (MMP-14) is a transmembrane MMP that plays a critical role in promoting angiogenesis. We investigated the expression levels of MMP-14 and correlated the levels with clinical disease activity and with the levels of the angiogenic factors vascular endothelial growth factor (VEGF) and MMP-9 in proliferative diabetic retinopathy (PDR). To reinforce the findings at the functional level, we examined the expression of MMP-14 in the retinas of diabetic rats.

Rho-Associated Protein Kinase-1 Mediates the Regulation of Inflammatory Markers in Diabetic Retina and in Retinal Müller Cells.

Goal: To investigate the effects of blocking Rho kinase pathway on the expression of inflammatory signaling pathways in the retina of diabetic mice and in human retinal Müller glial cells stimulated with high-glucose to replicate hyperglycemia.

Procedures: Retinas from diabetic mice and human retinal Müller glial cells (MIO-M1) were studied. Western blot analysis, immunofluorescence, and enzyme-linked immunosorbent assay were utilized to study the effect of the Rho kinase inhibitor fasudil on the expression of Rho-associated protein kinase-1 (ROCK-1), extracellular signal-regulated kinases1&2(ERK ½), phosphorylated nuclear factor kappa-light-chain-enhancer of activated B cells (p-NF-κB), inducible nitric oxide synthase (iNOS), vascular endothelial growth factor (VEGF), and monocyte chemoattractant protein-1 (MCP-1/CCL2).

Association of HMGB1 with oxidative stress markers and regulators in PDR.

Purpose: We investigated the link among the proinflammatory cytokine high-mobility group box 1 (HMGB1) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a marker of oxidative DNA damage, the endothelial adhesion molecule and oxidase enzyme vascular adhesion protein-1 (VAP-1), and the inducible cytoprotective molecule heme oxygenase-1 (HO-1) in proliferative diabetic retinopathy (PDR). We correlated the levels of these molecules with clinical disease activity and studied the proinflammatory activities of HMGB1 on rat retinas and human retinal microvascular endothelial cells (HRMECs).

Methods: Vitreous samples from 47 PDR and 19 non-diabetic patients, epiretinal membranes from 11 patients with PDR, human retinas (16 from diabetic patients and 16 from non-diabetic subjects), rat retinas, and HRMECs were studied by enzyme-linked immunosorbent assay, immunohistochemistry, western blot immunofluorescence, and RT-PCR analyses.

Association of 150-kDa oxygen-regulated protein with vascular endothelial growth factor in proliferative diabetic retinopathy.

Purpose: 150-kDa oxygen-regulated protein (ORP150), a member of heat-shock protein family located in endoplasmic reticulum (ER), has a critical role in secretion of vascular endothelial growth factor (VEGF). We investigated expression levels of ORP150 and correlated these levels with VEGF and total vitreous antioxidant capacity (TAC) in proliferative diabetic retinopathy (PDR). We also examined expression of ORP150 in retinas of diabetic rats and in human retinal microvascular endothelial cells (HRMEC).

Unbalanced Vitreous Levels of Osteoprotegerin, RANKL, RANK, and TRAIL in Proliferative Diabetic Retinopathy.

Purpose: We investigated the expression of the proinflammatory and proangiogenic factor osteoprotegerin (OPG) and its ligands, receptor activator of nuclear factor-κB ligand (RANKL), tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), and the receptor RANK in proliferative diabetic retinopathy (PDR).

Materials And Methods: Vitreous samples from PDR and nondiabetic control patients and epiretinal membranes from PDR patients were studied by enzyme-linked immunosorbent assay, immunohistochemistry, and Western blot analysis.

Results: Vascular endothelial growth factor, OPG, and soluble RANK levels in vitreous samples from PDR patients were significantly higher than that in nondiabetic controls.

Differential expression and localization of human tissue inhibitors of metalloproteinases in proliferative diabetic retinopathy.

Purpose: Tissue inhibitors of metalloproteinases (TIMPs) block the catalysis by matrix metalloproteinases (MMPs) and have additional biologic activities, including regulation of cell growth and differentiation, apoptosis, angiogenesis and oncogenesis. We investigated the expression levels of all the four human TIMPs and correlated these levels with those of MMP-9 and vascular endothelial growth factor (VEGF) in proliferative diabetic retinopathy (PDR).

Methods: Vitreous samples from 38 PDR and 21 nondiabetic control patients and epiretinal membranes from 14 patients with PDR and 10 patients with proliferative vitreoretinopathy (PVR) were studied by enzyme-linked immunosorbent assay, Western blot analysis and immunohistochemistry.

Extracellular matrix metalloproteinase inducer (EMMPRIN) is a potential biomarker of angiogenesis in proliferative diabetic retinopathy.

Purpose: Extracellular matrix metalloproteinase inducer (EMMPRIN) promotes angiogenesis through matrix metalloproteinases (MMPs) and vascular endothelial growth factor (VEGF) production. We investigated the expression levels of EMMPRIN and correlated these levels with VEGF, MMP-1 and MMP-9 in proliferative diabetic retinopathy (PDR). In addition, we examined the expression of EMMPRIN in the retinas of diabetic rats and the effect of EMMPRIN on the induction of angiogenesis regulatory factors in human retinal microvascular endothelial cells (HRMECs).

Genetic Ablation of Extra Domain A of Fibronectin in Hypercholesterolemic Mice Improves Stroke Outcome by Reducing Thrombo-Inflammation.

Background: The fibronectin-splicing variant containing extra domain A (Fn-EDA) is present in negligible amounts in the plasma of healthy humans but markedly elevated in patients with comorbid conditions, including diabetes mellitus and hypercholesterolemia, which are risk factors for stroke. It remains unknown, however, whether Fn-EDA worsens stroke outcomes in such conditions. We determined the role of Fn-EDA in stroke outcome in a model of hypercholesterolemia, the apolipoprotein E-deficient (Apoe(-/-)) mouse.

Taurine ameliorates neurobehavioral, neurochemical and immunohistochemical changes in sporadic dementia of Alzheimer's type (SDAT) caused by intracerebroventricular streptozotocin in rats.

Oxidative loads in the brain are involved in age related impairments like learning and memory as well as neurodegeneration. Taurine, the most abundant free amino acid in humans has many potential health benefits through its anti-oxidant and anti-inflammatory properties. Therefore, we investigated the neuroprotective potential of taurine on oxidative stress, neuronal loss and memory impairments in streptozotocin model of cognitive impairments in rats.