1999 — 2000 |
Sheibani, Nader |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Pecam1 and Regulation of Angiogenesis
DESCRIPTION (Adapted from Investigator's abstract): Angiogenesis, the highly regulated process of new capillary formation rarely occurs in normal adults, but is necessary during embryogenesis, corpus luteum formation, and wound healing. Uncontrolled angiogenesis plays an important role in diseases such as rheumatoid arthritis, hemangiomas, tumor growth and metastasis. Development of effective agents which can inhibit angiogenesis has potential value in the treatment of these diseases. Thrombospondin 1 (TS1) and certain peptides derived from TS I block angiogenesis in vivo and inhibit the proliferation and migration of endothelial cells (ECs) in vitro. These investigators have shown that TS I is a major regulator of EC phenotype and its expression is sufficient to restore a normal phenotype and suppress hemangioma formation in Polyoma middle T transformed mouse brain ECs. This is mediated, at least in part, by complete suppression of platelet endothelial cell adhesion molecule- I (PECAM-1) expression, an important regulator of EC adhesion and angiogenesis. The main objective of this proposal is to delineate the expression and adhesive function of different PECAM- I isoforms and to characterize their signaling pathways in ECs. The expression pattern of TS I and PECAM- I isoforms will be examined in ECs of developing murine blood vessels by in situ hybridization and immunohistochemistry. Expression of different PECAM- I isoforms and/or their cytoplasmic chimeras in ECs will determine whether different isoforms have distinct roles in regulation of EC phenotype and require interactions with cytoplasmic proteins. The GST-PECAM- I cytoplasmic fusion proteins phosphorylated on their tyrosine, serine, and threonine residues will be utilized in pull down experiments to identify the signal transducing molecules which interact with PECAM- 1. Expression of PECAM- I isoforms or his-myc tagged cytoplasmic domains in an epithelial cell model (MDCK cells), which forms adherens junctions very similar to ECs, will illustrate whether they affect formation of adherens junctions and influence PECAM- I cellular adhesive and signaling functions. These studies will provide insight into the coordinated expression of TS 1 and PECAM- 1 isoforms and their interactive roles in regulating EC phenotype. Characterization of the intracellular proteins which interact with PECAM- I cytoplasmic domains will provide further knowledge of the signaling pathways which regulate PECAM- I adhesive functions. It is suggested that a therapeutic benefit can be derived by exploiting these signaling pathways to control the hypervascularization characteristic of arthritis.
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1 |
2001 — 2003 |
Sheibani, Nader |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Pecam-1 and Regulation of Angiogenesis @ University of Wisconsin Madison
DESCRIPTION (Adapted from Investigator's abstract): Angiogenesis, the highly regulated process of new capillary formation rarely occurs in normal adults, but is necessary during embryogenesis, corpus luteum formation, and wound healing. Uncontrolled angiogenesis plays an important role in diseases such as rheumatoid arthritis, hemangiomas, tumor growth and metastasis. Development of effective agents which can inhibit angiogenesis has potential value in the treatment of these diseases. Thrombospondin 1 (TS1) and certain peptides derived from TS I block angiogenesis in vivo and inhibit the proliferation and migration of endothelial cells (ECs) in vitro. These investigators have shown that TS I is a major regulator of EC phenotype and its expression is sufficient to restore a normal phenotype and suppress hemangioma formation in Polyoma middle T transformed mouse brain ECs. This is mediated, at least in part, by complete suppression of platelet endothelial cell adhesion molecule- I (PECAM-1) expression, an important regulator of EC adhesion and angiogenesis. The main objective of this proposal is to delineate the expression and adhesive function of different PECAM- I isoforms and to characterize their signaling pathways in ECs. The expression pattern of TS I and PECAM- I isoforms will be examined in ECs of developing murine blood vessels by in situ hybridization and immunohistochemistry. Expression of different PECAM- I isoforms and/or their cytoplasmic chimeras in ECs will determine whether different isoforms have distinct roles in regulation of EC phenotype and require interactions with cytoplasmic proteins. The GST-PECAM- I cytoplasmic fusion proteins phosphorylated on their tyrosine, serine, and threonine residues will be utilized in pull down experiments to identify the signal transducing molecules which interact with PECAM- 1. Expression of PECAM- I isoforms or his-myc tagged cytoplasmic domains in an epithelial cell model (MDCK cells), which forms adherens junctions very similar to ECs, will illustrate whether they affect formation of adherens junctions and influence PECAM- I cellular adhesive and signaling functions. These studies will provide insight into the coordinated expression of TS 1 and PECAM- 1 isoforms and their interactive roles in regulating EC phenotype. Characterization of the intracellular proteins which interact with PECAM- I cytoplasmic domains will provide further knowledge of the signaling pathways which regulate PECAM- I adhesive functions. It is suggested that a therapeutic benefit can be derived by exploiting these signaling pathways to control the hypervascularization characteristic of arthritis.
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1 |
2003 — 2005 |
Sheibani, Nader |
R03Activity Code Description: To provide research support specifically limited in time and amount for studies in categorical program areas. Small grants provide flexibility for initiating studies which are generally for preliminary short-term projects and are non-renewable. |
Thrombospondin-1 and Retininal Vascular Homeostasis @ University of Wisconsin Madison
DESCRIPTION (provided by applicant): Diabetes predominantly affects the microvascular circulation of the retina resulting in a range of structural changes that are unique to this tissue. These changes include an early persistent loss of pericytes from retinal microvessels, thickening of the basement membrane, followed by hyperproliferation of endothelial cells (ECs) and abnormal vascularization of the retina, which ultimately results in blindness. Retinal vascularization is normally restricted to the superficial and deep layers of the retina. Other ocular sites such as cornea, lens, and vitreous are normally vascular free. It has been hypothesized that a negative regulator of angiogenesis is responsible for these vascular restrictions. We have recently demonstrated that thrombospondin-1 (TSP1), a potent natural inhibitor of angiogenesis, is present at ocular avascular sites and TSPt expression is dramatically down regulated with diabetes. Our hypothesis is that TSP1 is an important modulator of retinal vascular homeostasis whose alterations under pathological conditions such as diabetes and/or ischemia results in retinal neovascularization. The studies proposed here will investigate the role of TSP1 in retinal vascular development and ischemia-induced neovascularization. We will examine the expression of TSP1 in the retina and retinal capillaries during development and determine whether its expression is altered during oxygen-induced ischemic retinopathy. We will compare development of retinal vasculature and their total area in the retina of normal, TSP1 deficient, and TSP1 over-expressing transgenic mice. We will determine whether lack or over-expression of TSP1 influences retinal vascular development and neovascularization in response to hypoxia. Identification of TSP1 as a modulator of ocular vascularization and the study of its mechanisms of action in retinal vascular cells will provide insight into the defects that contribute to retinal neovascularization. This knowledge will provide the rationale for development of new therapeutic approaches for the prevention and/or treatment of ocular diseases with a neovascular component.
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1 |
2007 — 2011 |
Sheibani, Nader |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Pecam-1 and Retinopathy of Prematurity @ University of Wisconsin-Madison
DESCRIPTION: Angiogenesis is required for proper development of the embryonic circulatory system and is an important step in the progression of many eye diseases, including retinopathy of prematurity (ROP). Therefore, understanding how the normal regulatory systems in the endothelium keep angiogenesis in check has great clinical implications. Platelet endothelial cell adhesion molecule-1 (PECAM-1) is an important regulator of angiogenesis. We have shown that multiple isoforms of PECAM-1 are expressed in vascular beds of different tissues in a developmentally regulated fashion. The ability of these isoforms to differentially activate intracellular signaling pathways suggests specific roles for these isoforms during vascular development and angiogenesis. However, the physiological role PECAM-1 and its isoforms play in these processes requires further investigation. The main objective of this proposal is to delineate the physiological role of PECAM-1 and its isoforms in retinal vascular development and angiogenesis, as well as in regulation of retinal EC adhesive and migratory properties, and to elucidate the function of genes whose endothelium expression is differentially regulated by PECAM-1. Specifically, we will demonstrate the role of PECAM-1 in the development of retinal vasculature and neovascularization and determine how these processes are affected in the absence of PECAM-1. We will determine the expression pattern of PECAM-1 isoforms during retinal vascular development and neovascularization, as well as in retinal endothelial cells (EC). We will evaluate the specific roles of PECAM-1 isoforms in the regulation of EC adhesion and migration. To further elucidate PECAM-1's mechanism of action, we will identify and perform functional studies of genes such as endoglin and connective tissue growth factor whose endothelium-specific expression is differentially affected by the lack of PECAM-1. These studies will provide insight into the physiological role of PECAM-1 in retinal vascular development and angiogenesis and in modulation of EC adhesion and migration. This knowledge will be instrumental in the development of new treatment modalities for a variety of eye diseases with a neovascular component.
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1 |
2009 — 2010 |
Sheibani, Nader |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Cyp1b1 and Retinopathy of Prematurity @ University of Wisconsin-Madison
The expression of specific cytochrome P450s (CYPs) in vascular smooth muscle cells and endothelial cells (EC). and the critical contribution of their products to vascular function suggest important roles for these genes in vascular homeostasis. Although lack of CYP1 B1 is shown to influence the function and development of the trabecular meshwork. Its physiological role in the development of retinal vasculature and angiogenesis has not been previously studied. Our preliminary data indicate that CYP1 B1 plays an essential role in retinal vascular development and neovascularization during oxygen-induced ischemic retinopathy (aiR). The CYP1 B1-deficient (CYP1 B1-/-) mice exhibit reduced retinal vascular density and fail to neovascularize their retina during aiR. Furthermore. retinal EC prepared from CYP1B1-/- mice are less migratory and fail to undergo capillary morphogenesis in Matrigel. These cells also express increased amounts of thrombospondin-2 (TSP2). an endogenous inhibitor of angiogenesis whose expression is modulated by cellular oxidative stress. Our hypothesis is that CYP1 B1 plays a central role in maintaining the redox state of the endothelium in check, such that in its absence increased oxidative stress promotes sustained activation of NF-KB and TSP2 expression, and inhibits angiogenesis. We have now shown that changes in TSP2 expression mediate the effects of CYP1 B1-deficiency on retinal vascularization in vivo and capillary morphogenesis of retinal EC in culture. We have also shown increased oxidative state mediates these effects of CYP1B1-deficiency on retinal neovascularization during OIR and can be reversed in the presence of an antioxidant. In addition changes in CYP1 B 1 expression are sufficient to affect TSP2 expression and retinal EC capillary morphogenesis in vitro. Therefore these changes are modulated by the intracellular oxidative stress in a CYP1 B1 dependent manner. Here we will determine the source of reactive oxygen species and will delineate the potential regulatory role of redox sensitive transcription factors NF-KB in increased TSP2 expression. We will also determine whether expression of NF-KB is modulated by CYP1 B1 through removal of oxygenation products. Understanding how CYP1 B1 and its metabolites regulate retinal vascular homeostasis will provide insight into CYP1 B1 mechanisms of action and aid in the development of alternative ways to modulate retinal angiogenesis.
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1 |
2010 |
Assadi, Amir H (co-PI) [⬀] Assadi-Porter, Fariba M Sheibani, Nader Zhang, Hao F (co-PI) [⬀] |
RC4Activity Code Description: To support multi-year funded research with high impact ideas that may lay the foundation for new fields of investigation; accelerate breakthroughs; stimulate early and applied research on cutting-edge technologies; foster new approaches to improve the interactions among multi- and interdisciplinary research teams; or, advance the research enterprise in a way that could stimulate future growth and investments and advance public health and health care delivery. This activity code could support either a specific research question or propose the creation of a unique infrastructure/resource designed to accelerate scientific progress in the future. It is the multi-year funded companion activity code to the existing RC2; thus ICs need OER prior approval to use the RC4. |
Integrated Multidisciplinary Strategies For Detection of Diabetic Retinopathies @ University of Wisconsin-Madison
DESCRIPTION (provided by applicant): The significance and nature of this collaboration fits very well with the thematic areas applying genomics and other high throughput technologies, translating basic science discoveries into new and better treatment, using science to enable health care reform, and reinvigorating the biomedical community. Diabetes predominantly affects the microvascular circulation of the retina and results in a range of microvascular structural changes that are unique to this tissue. The clinical course of diabetic retinopathy is classified into stages reflecting the progression of the disease and the prognostic risk of blindness. It is assumed that the full spectrum of diabetic retinal microangiopathy arises from a continuum, and that one stage of the disease is likely to lead to another, more advanced stage with a greater risk for blindness. These stages include "no retinopathy", "nonproliferative", and (mild, moderate, severe) "proliferative" retinopathy. Two of the earliest histopathological lesions, diffuse thickening of the basement membrane and selective loss of pericytes, go undetected by routine fundus examinations. Our hypothesis is that these changes have significant impact on retinal vascular hemodynamic and oxygenation, which can be detected non-invasively, utilizing a novel multimodal imaging methodology developed by our group. Here we have assembled a team of investigators to take full advantage of the frontiers of computational, engineering, biological, and biochemical analysis to address a major clinical concern, namely detection of early retinopathies associated with diabetes. As a proof of concept, we purpose to further develop and adopt a multimodal retinal functional imaging, complemented with various high throughput biochemical and computational analysis for study of early diabetic changes in novel mouse models of diabetes developed by our group. We will utilize metabolomic changes of the retina and serum prepared from animals with different duration of diabetes, as well as gene expression profiling of retinal samples, and retinal vascular cells under normal and high glucose, to further identify specific early changes during diabetes. Our group has developed and has the expertise to design and implement unique algorithm for large data set analysis and modeling based on specific genotypic and phenotypic variations. In addition, we have computational expertise to improve our imaging capabilities and qualities. Our team will be able to successfully implement the research proposed here and integrate our findings in a meaningful way which could be readily adapted for diagnosis and treatment strategies in humans. Detection and identification of the molecular and cellular bases of early changes that progress to advance stages of the disease will allow for a better diagnosis, prevention and treatment modalities. PUBLIC HEALTH RELEVANCE: Diabetes affects retinal circulation resulting in vascular abnormalities that ultimately lead to aggressive growth of new vessels and loss of vision. A clear understanding of how these changes are brought about, and their early non-invasive detection and identification of their molecular and cellular bases, are essential in advancing our understanding of diabetic retinopathy. This knowledge will lead to the development of better and more effective therapies. Factors that keep retinal vasculature in check, such as thrombospondin-1 and vascular endothelial growth factor play a major role in normal retinal vascular function. Alterations in these factors during diabetes may contribute to abnormal vascular function and growth of new blood vessels. Increased production of vascular endothelial growth factor, which promotes growth of new vessels and alters vascular permeability, has been demonstrated during diabetes. Here Dr. Sheibani and his team of collaborators will utilize an integrated strategy to detect and determine the biochemical and gene specific changes, such as thrombospondin-1, in development and progression of retinopathies during diabetes. This knowledge will be instrumental in accelerating our progress in the understanding, detection, and treatment of diabetic retinopathy.
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1 |
2013 — 2017 |
Sheibani, Nader |
R24Activity Code Description: Undocumented code - click on the grant title for more information. |
Novel Antiangiogenic Peptides For Treatment of Exudative Amd @ University of Wisconsin-Madison
DESCRIPTION (provided by applicant): An interdisciplinary consortium of investigators from the Departments of Ophthalmology and Pediatrics at the University of Wisconsin in collaboration with the Northwestern University Chemistry of Life Processes Institute, Biomedical Engineering, Urology, and Pediatrics, and the University of Nebraska Center for Drug Delivery and Nanomedicine, proposes to increase the pace at which basic science discoveries on disease mechanisms can be translated into therapies for exudative age-related macular degeneration (AMD), a stated goal of the R24 National Eye Institute Translational Research Program on Therapy for Visual Disorders. This scientific partnership will employ its diverse scientific expertise to characterize and test potential therapies for exudative AMD in animal models by using a combination of cutting-edge physiological, chemical, analytical and imaging approaches. By screening novel peptides derived from endogenous inhibitors of angiogenesis for their ability to prevent neovascularization in animal models that mimic AMD, we will accelerate drug development before testing in humans. Improving drug delivery to the eye as an integral part of these experiments will also be a high priority. Specific goals of this project are to: (1) determin whether the peptide mechanisms of action in the eye are through their mimicry of these natural inhibitors; (2) Produce and identify optimal new derivatives of benchmark peptides best suited to intravitreal treatment of AMD, where these are ranked by efficacy in CNV models, individually and in combination; (3) Select and tested the most active peptide(s) and their most slowly cleared formulations for efficacy in AMD models. The best candidate(s) will undergo GLP production and then safety testing, including retinal safety to select a suitable new peptide-based entity for clinical development; and (4) Establish preclinical basis for ultimate human treatment protocol for this entity through animal models of retinal disease examined via state-of-the art in vivo retinal imaging and histopathological analysis. Ultimately, the experimental result of these interrelated aims will guide us in developing more successful therapies for those afflicted by currently incurable blinding diseases with a neovascular component.
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1 |
2016 — 2020 |
Sheibani, Nader Zhang, Hao F [⬀] |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Investigating Oxygen Metabolism in Diabetic Retinopathy @ Northwestern University
PROJECT SUMMARY Diabetic retinopathy (DR) is a leading cause of blindness in the US and one of the major complications of both Type 1 and Type 2 diabetes. Although DR is widely accepted to be an ischemia-driven disease, the current diagnosis and grading of DR severity is based solely on anatomic alterations such as the quantification of abnormal retinal microvasculature in non-proliferative disease or angiogenesis in proliferative stages. As a result, retinal impairment is irreversible in most DR patients when diagnosed, largely due to the lack of technology to quantify retinal ischemia and the lack of knowledge of the underlying mechanism of retinal ischemia. This proposal aims to investigate retinal ischemia in early diabetes using a novel optical coherence tomography technology, which offers the capability to quantify metabolic rate of oxygen (MRO2) in the retina for the first time. We refer to this new technology as visible-light optical coherence tomography or vis-OCT. We seek to identify when MRO2 alterations initially occur, the causes of MRO2 alterations, and whether intervention of MRO2 affects the development of DR in a unique Type 1 mouse model. At the end of the project period, we will have 1) established a time line and mechanistic knowledge of retinal MRO2 changes during the development and progression of DR and 2) fully-optimized the vis-OCT system that is ready to be translated for the next-stage patient testing.
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0.942 |