NEURAL STABILITY AFTER RETINAL DETACHMENT
P Ian
Univ Of Med/dent Of Nj-nj Medical Schoolcity: Newark country: United States (us)
Grant 1R01EY021542-01A1 from National Eye Institute
Abstract: Visual recovery after repair of a retinal detachment is often disappointing with more than half of treated patients reporting below normal visual acuity. Retinal neurons undergo dramatic structural plasticity after detachment including retraction of rod axons, rounding of cone terminals, and sprouting by bipolar and horizontal cells. Some of these changes occur within hours after retinal injury in animal models. It has been suggested that this synaptic remodeling contributes to poor visual recovery. In retinal cell cultures, activation of the RhoA-Rho kinase (ROCK) signaling cascade is primarily responsible for rod axon retraction. Thus, this application tests the hypothesis that a combined therapy of RhoA-antagonists and retinal surgery may significantly improve the visual outcome after repair of a detached retina by preventing or reducing synaptic plasticity. This hypothesis will be tested on adult pigs, whose eyes are similar to human eyes, focusing on the following specific aims 1) To test whether RhoA antagonists which inhibit the activity of RhoA, ROCK, or their substrates will prevent the structural synaptic changes caused by detachment including rod axon retraction, rod-bipolar synaptic dissolution, cone terminal morphological change, and bipolar cell sprouting. The effect on glial cell reactivity will also be examined; 2) To determine whether RhoA-related drugs can be applied after a detachment, a more therapeutically relevant scenario, and if so, how long after the injury; and 3) To determine if detached retinas treated with RhoA-related drugs indeed help visual structural and functional recovery after reattachment surgery. Morphology will be assessed by immunohistochemistry, image analysis and confocal laser scanning and electron microscopy. Levels of activity and the time-course of Rho signaling will be determined by biochemical assays for multiple components including RhoA activation and myosin light chain phosphorylation. Retinal function after reattachment will be assessed by electroretinograms. Some of the drugs that will be tested (Ct-04 and fasudil) have already been approved for human use. We hope to establish the approximate dosage and mode of application to be tested in patients, if RhoA antagonists prove to be a useful adjunct to surgical reattachment. Visual outcomes after repair of retinal detachment remain disappointing even years after successful reattachment surgery. Based on the effectiveness of preventing deleterious photoreceptor synaptic change, in vitro, a new therapy is proposed for retinal detachment. The therapy consists of intraocular application of RhoA antagonists combined with relatively rapid retinal reattachment
Keywords: Adult; Animal Model; Axon; base; Biochemical; Biological Assay; Brain Injuries; Cell Culture Techniques; Cells; central nervous system injury; cytotoxicity; Data; Degenerative Disorder; density; design; dosage; drug testing; Effectiveness; Electron Microscopy; Electrons; Electroretinography; Elements; Eye; Family suidae; fasudil; Glial Fibrillary Acidic Protein; Goals; Guanosine Triphosphate Phosphohydrolases; horizontal cell; Hour; Human; Image Analysis; immunocytochemistry; Immunohistochemistry; improved; In Vitro; in vivo Model; Injection of therapeutic agent; Injury; Lasers; Light; light microscopy; LIM Domain Kinase 1; Microscopic; Microscopy, Electron, Scanning; Modification; Morphology; Muller`s cell; Myosin Light Chain Kinase; Myosin Light Chains; Neuraxis; Neuroglia; Operative Surgical Procedures; Outcome; Patients; Pharmaceutical Preparations; Phosphorylation; Phosphotransferases; Photoreceptors; Presynaptic Terminals; prevent; Prevention; Publishing; Recovery; Recovery of Function; relating to nervous system; repaired; Reporting; research study; response to injury; Retina; Retinal; Retinal Cone; Retinal Detachment; retinal neuron; rho; Rho-associated kinase; Rods (Retina); Signal Pathway; Signal Transduction; Site; Spinal cord injury; Structure; Synapses; Synaptic plasticity; Testing; therapeutic target; Time; Up-Regulation (Physiology); Vision; Visual; Visual Acuity; Visual system structure; Western Blotting
Relevance: Visual outcomes after repair of retinal detachment remain disappointing even years after successful reattachment surgery. Based on the effectiveness of preventing deleterious photoreceptor synaptic change, in vitro, a new therapy is proposed for retinal detachment. The therapy consists of intraocular application of RhoA antagonists combined with relatively rapid retinal reattachment
Project start date: 2012-02-01
Project end date: 2017-01-31
Budget start date: 1-FEB-2012
Budget end date: 31-JAN-2013
1R01EY021542-01A1 (2012): $372675
Sponsored Links Excellgen http://Excellgen.com
Grants awarded to P Ian
NOVEL PATHWAYS FOR BCR-ABL TRANSFORMATION
P Ian, Associate Professor
Univ Of Med/dent Of Nj-nj Medical Schoolcity: Newark country: United States (us)
Grant 5R01CA097066-08 from National Cancer Institute
Abstract: Numerous animal studies have demonstrated that the fusion protein p210 Bcr-Abl is the causative agent of Chronic Myelogenous Leukemia (CML), and pharmacological inhibitors (such as imatinib) that target this molecule produce effective, durable responses in many patients. Imatinib targets a tyrosine kinase activity contained within the Abl sequences that is considered to be the principle driving force behind CML. Although the success of imatinib has validated rational drug design in cancer therapy, two clinical issues are emerging in the treatment of CML. First, patients are developing resistance to imatinib by acquiring mutations within the kinase domain (acquired resistance). Second, and probably more problematic, over 95% of patients still have p210 Bcr-Abl positive cells, even after 12 months of imatinib treatment (minimal residual disease). Whether or not acquired resistance and minimal residual disease are mechanistically related is unclear, but both problems highlight the need to develop complementary inhibitors, with different modalities, that can target additional functions of p210 Bcr-Abl. Although the tumorigenic properties of p210 Bcr-Abl can be primarily attributed to the Abl-encoded kinase activity, numerous studies have determined that there are also domains present within the Bcr sequences that are required to support oncogenic activity. Although poorly characterized, these domains are intriguing since they represent unexploited targets for pharmacological intervention. In the previous funding period, our laboratory as been exploring the hypothesis that the characterization of Bcr- encoded activities will identify viable new targets for p210 Bcr-Abl inhibition. Three such activities have now been identified. First, it has been determined that the RhoGEF domain, which is autoinhibited in Bcr, is constitutively activated in p210 Bcr-Abl. Mutations that eliminate this activity in p210 Bcr-Abl exhibit diminished transforming activity in cell- and animal-based models suggesting that this domain may be required for CML. Second, it has been determined that Bcr is a regulatory component of the endosomal sorting pathway, and that this pathway is disrupted by overexpression of p210 Bcr-Abl in hematopoietic cells. This represents a novel, and completely unexplored aspect of p210 Bcr-Abl biology, which undoubtedly will be relevant to CML. Finally, it has been determined that Bcr has a nuclear function through which it can regulate levels of protein expression. This includes the c-Myc oncoprotein which is known to contribute to CML. Bcr-Abl regulates c- Myc through binding to XPB, and disruption of this interaction is also associated with diminished transforming activity in cell- and animal-based models. In this continuation application these activities will be characterized in the context of hematopoietic cells, and it will be determined whether they are viable targets for p210 Bcr-Abl inhibition. For this analysis, p210 Bcr-Abl mutants have been generated that are impaired in these activities, and which can be evaluated in cell- and animal-based models for CML. Imatinib is a pharmacological inhibitor that causes clinical remission in many patients with Chronic Myelogenous Leukemia. However, imatinib controls rather than cures the disease, and many patients develop resistance to the treatment. Thus, the focus of this proposal is the development of novel approaches and inhibitors that can be used to complement imatinib treatment
Keywords: Agreement; Allogenic; Animals; Apoptosis; base; bcr-abl Fusion Proteins; Binding (Molecular Function); Binding Sites; Biology; c-myc Genes; cancer therapy; Cell Nucleus; Cells; Chimeric Proteins; Chronic Myeloid Leukemia; Clinical; clinical remission; Complement; Complex; Cytoplasm; Development; DH Domain; Disease; Docking; driving force; Drug Design; Endosomes; Epidermal Growth Factor Receptor; ERCC3 gene; Exhibits; Funding; Goals; Health; Hematopoietic; Imatinib; inhibitor/antagonist; Intervention; Laboratories; Malignant Neoplasms; Maps; Mediating; Modality; Modeling; mutant; Mutation; novel; novel strategies; Nuclear; Nuclear Matrix; Nucleotide Excision Repair; Oncogene Proteins; Oncogenic; overexpression; Pathogenesis; Pathway interactions; Patients; Phosphotransferases; Property; protein expression; Protein Tyrosine Kinase; Proteins; Radiation; Repair Complex; Residual Neoplasm; Resistance; Resistance development; response; rho; Role; Signal Transduction; Site; Sorting - Cell Movement; Stem cell transplant; success; Testing; Transcript; transcription factor TFIIH; treatment strategy; tumorigenic; Ubiquitin
Project start date: 2002-07-01
Project end date: 2013-05-31
Budget start date: 1-JUN-2011
Budget end date: 31-MAY-2012
PFA/PA: PA-07-070
5R01CA097066-08 (2011): $270909