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. Hence, targeting VEGF or VEGF‐mediated molecular pathways could be an excellent therapeutic strategy for managing cancers and intraocular neovascular disorders. Although anti‐VEGF therapies, such as monoclonal antibodies and small‐molecule tyrosine kinase inhibitors, have limited clinical efficacy, they can still significantly improve the overall survival rate. This thus demands further investigation through the development of alternative strategies in the management of VEGF‐mediated pathological angiogenesis. This review article focuses on the recent developments toward the delineation of the functional biology of VEGF and the role of anti‐VEGF strategies in the management of tumor and eye pathologies. Moreover, therapeutic angiogenesis, an exciting frontier for the treatment of ischemic disorders, is highlighted in this review, including wound healing.
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. CD40L and CD40 levels were significantly increased in PDR vitreous samples. We demonstrated CD40L and CD40 expression in vascular endothelial cells, leukocytes and myofibroblasts in epiretinal membranes. Intravitreal administration of soluble (s)CD40L in normal rats significantly increased retinal vascular permeability and induced significant upregulation of phospho-ERK1/2, VEGF, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). sCD40L induced upregulation of VEGF, MMP-9, MCP-1 and HMGB1 in cultured Müller cells and phospo-ERK1/2, p65 subunit of NF-ĸB, VCAM-1 and VEGF in cultured HRMECS. TNF-α induced significant upregulation of CD40 in HRMECs and Müller cells and VEGF induced significant upregulation of CD40 in HRMECs. sCD40L induced proliferation and migration of HRMECs. We provide experimental evidence supporting the involvement of the CD40L-CD40 pathway and how it regulates inflammatory angiogenesis in PDR.
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. Mechanistically, deletion of AKAP1 dysregulates complex II of the electron transport chain, increases superoxide production, and impairs Ca
homeostasis in neurons subjected to excitotoxic glutamate. Ca
deregulation in neurons lacking AKAP1 can be attributed to loss of inhibitory phosphorylation of the mitochondrial fission enzyme dynamin-related protein 1 (Drp1) at the protein kinase A (PKA) site Ser637. Our results indicate that inhibition of Drp1-dependent mitochondrial fission by the outer mitochondrial AKAP1/PKA complex protects neurons from ischemic stroke by maintaining respiratory chain activity, inhibiting superoxide production, and delaying Ca
deregulation. They also provide the first genetic evidence that Drp1 inhibition may be of therapeutic relevance for the treatment of stroke and neurodegeneration.
Previous work suggests that activation of dynamin-related protein 1 (Drp1) and mitochondrial fission contribute to ischemic injury in the brain. However, the specificity and efficacy of the pharmacological Drp1 inhibitor mdivi-1 that was used has now been discredited by several high-profile studies. Our report is timely and highly impactful because it provides the first evidence that genetic disinhibition of Drp1 via knock-out of the mitochondrial protein kinase A (PKA) scaffold AKAP1 exacerbates stroke injury in mice. Mechanistically, we show that electron transport deficiency, increased superoxide production, and Ca
overload result from genetic disinhibition of Drp1. In summary, our work settles current controversies regarding the role of mitochondrial fission in neuronal injury, provides mechanisms, and suggests that fission inhibitors hold promise as future therapeutic agents.
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. Both full-length and cleaved activation/degradation fragments of ADAMTS proteinases were identified. The amounts of versican and biglycan cleavage products were increased in vitreous from PDR patients. ADAMTS proteinases and MMP-15 were localized in endothelial cells, monocytes/macrophages and myofibroblasts in PDR membranes, and ADAMTS-4 was expressed in the highest number of stromal cells. The angiogenic activity of PDR membranes correlated significantly with levels of ADAMTS-1 and -4 cellular expression. ADAMTS proteinases and MMP-15 were expressed in rat retinas. ADAMTS-1 and -5 and MMP-15 levels were increased in diabetic rat retinas. HRMECs and Müller cells constitutively expressed ADAMTS proteinases but not MMP-15. The inhibition of NF-κB significantly attenuated the TNF-α-and-VEGF-induced upregulation of ADAMTS-1 and -4 in a culture medium of HRMECs and Müller cells. In conclusion, ADAMTS proteinases, MMP-15 and versican and biglycan cleavage products were increased in the ocular microenvironment of patients with PDR.
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. Here we determine the protective effects of a plant-derived NOX inhibitor apocynin (APO) on NOX4-induced ROS production which may contribute to the depletion of survival factors BDNF/SIRT1 or cell death in the diabetic retinas. Human retinal Müller glial cells (MGCs) were treated with hypoxia mimetic agent cobalt chloride (CoCl
2
) in the absence or presence of APO. Molecular analysis demonstrates that NOX4 is upregulated in CoCl
2
-treated MGCs and in the diabetic retinas. Increased NOX4 was accompanied by the downregulation of BDNF/SIRT1 expression or in the activation of apoptotic marker caspase-3. Whereas, APO treatment downregulates NOX4 and subsequently upregulates BDNF/SIRT1 or alleviate caspase-3 expression. Accordingly, in the diabetic retina we found a positive correlation in NOX4 vs ROS (p = 0.025; R
2
= 0.488) and caspase-3 vs ROS (p = 0.04; R
2
= 0.428); whereas a negative correlation in BDNF vs ROS (p = 0.009; R
2
= 0.596) and SIRT1 vs ROS (p = 0.0003; R
2
= 0.817) respectively. Taken together, NOX4-derived ROS could be a main contributor in downregulating BDNF/SIRT1 expression or in the activation of caspase-3. Whereas, APO treatment may minimize the deleterious effects occurring due to hyperglycemia and/or diabetic mimic hypoxic condition in early pathogenesis of DR.
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. In recent years, flavonoids with their diverse physico-biological properties have gained the scientific community's attention for the treatment of various forms of cancer. Different flavonoids, especially, flavonols (quercetin, kaempferol, fisetin, and isorhamnetin), flavanones (hesperidin and naringin), and anthocyanins, have shown potent anticancer activities affecting various signaling cascades. Among those, phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/ mammalian target of rapamycin (mTOR) signaling pathway is widely known to play a significant role in different physio-cellular activities, which triggers malignant transformation and is considered a key target for anticancer compounds. This pathway plays a vital role in regulating the cell cycle, metabolism, survival, and proliferation. The flavonoids exhibit their anticancer activity via different molecular pathways, including PI3K/Akt/mTOR. In the current piece of paper, our focus is to underpin the action of the above-mentioned flavonoids against different cancers, mainly covering in-vitro data, through PI3K/Akt/mTOR targeting.
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. We detected significant positive correlations between the levels of MIF and the levels of sICAM-1 (
= 0.43;
= 0.001) and VEGF (
= 0.7;
< 0.001). Through immunohistochemical analysis of PDR epiretinal membranes, significant positive correlations were also found between microvessel density (CD31 expression) and the numbers of blood vessels expressing MIF (
= 0.56;
= 0.045) and stromal cells expressing MIF (
= 0.79;
= 0.001) and CD74 (
= 0.59;
= 0.045). Similar to VEGF, MIF was induced in Müller cells cultured under hypoxic conditions and MIF induced phosphorylation of ERK1/2 and VEGF production in Müller cells. Intravitreal administration of MIF in normal rats induced increased retinal vascular permeability and significant upregulation of phospho-ERK1/2, NF-κB, ICAM-1 and vascular cell adhesion molecule-1 expression in the retina. MIF induced migration and proliferation of human retinal microvascular endothelial cells. These results suggest that MIF/CD74 signaling is involved in PDR angiogenesis.
In the present study, we examined the molecular mechanism by which Piperine (bioactive compound of Piper nigrum) inhibits neuronal cell apoptosis. We further investigated the anti-inflammatory effect ...of Piperine on 6-OHDA induced Parkinson's disease. Consistent with its antioxidant properties, Piperine (10mg/kg bwt) reduced 6-OHDA-induced lipid peroxidation and stimulated glutathione levels in striatum of rats. Furthermore, Piperine treatment diminished cytochrome-c release from mitochondria and reduced caspase-3 and caspase-9 activation induced by 6-OHDA. Treatment with Piperine markedly inhibited poly(ADP-ribose) polymerase activation, pro-apoptotic Bax levels and elevation of Bcl-2 levels. Piperine reduces contralateral rotations induced by apomorphine. Further narrow beam test and rotarod also showed improvement in motor coordination and balance behavior in rats treated with Piperine. In addition Piperine depletes inflammatory markers, TNF-α and IL-1β in 6-OHDA-induced Parkinson's rats. We propose that, in addition to its antioxidant properties Piperine exerts a protective effect via anti-apoptotic and anti-inflammatory mechanism on 6-OHDA induced Parkinson's disease.
Abstract Recent evidence indicates that curcumin (CUR), the principal curcuminoid of turmeric, exhibits antioxidant potential and protects the brain against various oxidative stressors. The aim of ...the present study was to examine the modulating impacts of CUR against cognitive deficits and oxidative damage in intracerebroventricular–streptozotocin (ICV–STZ) infused rats. Rats were injected bilaterally with ICV–STZ (3 mg/kg), while sham rats received the same volume of vehicle and then supplemented with CUR (80 mg/kg) for three weeks. After two weeks of ICV–STZ infusion, rats were tested for cognitive performance using passive avoidance and water maze tasks and then sacrificed for biochemical and histopathological assays. ICV–STZ rats showed significant cognitive deficits, which were significantly improved by CUR supplementation. CUR supplementation significantly augmented increased 4-hydroxynonenal (4-HNE) and malonaldehyde (MDA), thiobarbituric reactive substances (TBARS), hydrogen peroxide (H2 O2 ), protein carbonyl (PC) and oxidized glutathione (GSSG); decreased levels of reduced glutathione (GSH) and its dependent enzymes (Glutathione peroxidase GPx and glutathione reductase GR) in the hippocampus and cerebral cortex; and increased choline acetyltransferase (ChAT) activity in the hippocampus of ICV–STZ rats. The study suggests that CUR is effective in preventing cognitive deficits, and might be beneficial for the treatment of sporadic dementia of Alzheimer's type (SDAT).
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.
In a transient cerebral ischemia/reperfusion injury model, Apoe(-/-) mice expressing fibronectin deficient in EDA (Fn-EDA(-/-)Apoe(-/-) mice) exhibited smaller infarcts and improved neurological outcomes at days 1 and 8 (P<0.05 versus Apoe(-/-) mice). Concomitantly, intracerebral thrombosis assessed by fibrin(ogen) deposition and postischemic inflammation (phospho-nuclear factor-κB p65, phospho-IκB kinase α/β, interleukin 1β, and tumor necrosis factor-α) within lesions of Fn-EDA(-/-)Apoe(-/-) mice were markedly decreased (P<0.05 versus Apoe(-/-) mice). In an FeCl3 injury-induced carotid artery thrombosis model, thrombus growth rate and the time to occlusion were prolonged in Fn-EDA(-/-)Apoe(-/-) mice (P<0.05 versus Apoe(-/-) mice). Genetic ablation of TLR4 improved stroke outcome in Apoe(-/-) mice (P<0.05) but had no effect on stroke outcome in Fn-EDA(-/-)Apoe(-/-) mice. Bone marrow transplantation experiments revealed that nonhematopoietic cell-derived Fn-EDA exacerbates stroke through Toll-like receptor-4 expressed on hematopoietic cells. Infusion of a specific inhibitor of Fn-EDA into Apoe(-/-) mouse 15 minutes after reperfusion significantly improved stroke outcome.
Hypercholesterolemic mice deficient in Fn-EDA exhibit reduced cerebral thrombosis and less inflammatory response after ischemia/reperfusion injury. These findings suggest that targeting Fn-EDA could be an effective therapeutic strategy in stroke associated with hypercholesterolemia.
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