Zahoor Shah - US grants

[unreadable] DESCRIPTION (provided by applicant): My expertise and skill in neurosurgery, particularly in small animal models, together with my knowledge of herbal drugs and proteomics are essential to the advancement of research in the field of stroke and ischemic brain damage. Because stroke is the third most common cause of death in the US, research in this field is of great importance. I have made a number of contributions to this clinically relevant problem. For example, I have recently published an optimized method for producing transient stroke in mice, and have been optimizing a permanent model of ischemia also. I have used both of these methods to test the beneficial properties of other well standardized herbal plant extracts and their bioactive components against stroke. My long term goals involve researching natural products, such as Ginkgo biloba (EGb 761), to find novel mechanisms for preventing and treating stroke and ischemia-related brain injury. While starting my fifth year of postdoctoral training, my immediate goal is to become an independent researcher in the cutting-edge research of neuronal damage associated with ischemia. In addition to my experience in stroke and herbal medicine, this proposal will allow me to complete my training in behavioral science and molecular biology which is necessary to reach my independent career goals. I will work with my mentor, Dr. Dore, who has extensive expertise in neuronal dysfunction associated with stroke and other neurodegenerative diseases and has a proven record of training fellows. The training environment also involves a team of top researchers in behavioral neuroscience, stroke, and aging at the Johns Hopkins School of Medicine. The K99/R00 award will allow me the time and support necessary to work toward my research goals. The main goal of the proposed project is to determine the neuroprotective effect and mechanism of actions of EGb in ischemic brain injury by using permanent, transient, and global models of ischemia. We have accumulated evidence that heme oxygenase 1 (HO1) activity reduces ischemic brain injury, and we hypothesize that EGb provides neuroprotection by inducing HO1. To determine the role of HO1 in EGb neuroprotection, we will subject wildtype mice and mice with targeted deletion of HO1 (HOT'") to models of ischemia and compare the effect of EGb pre- and post-treatment on injury size. We will also optimize the therapeutic dose and window. We will address possible mechanisms of protection by measuring cerebral blood flow, hippocampal cell death, HO1 expression, and functional outcomes in various in vitro and in vivo ischemia models. This research proposal will have direct pre-clinical relevance by 1) determining the efficacy of EGb in treating or preventing stroke-related injury, 2) determining the optimal dose and time frame for EGb use, and 3) providing information for clinicians and their patients regarding the prophylactic use of Ginkgo extract, EGb. [unreadable] [unreadable] [unreadable] [unreadable]

Hemorrhagic stroke constitutes only 10-15% of total stroke types but is responsible for higher mortality rates and survivors suffer from severe disabilities and post-stroke cognitive impairments (PSCI). Except for surgical intervention, there is no effective treatment for intracerebral hemorrhage (ICH). In order to develop effective treatment modalities, it is imperative to gain a better understanding of the pathways that are active after ICH, in particular, during secondary injury involving microglial activation mediated neuroinflammation and PSCI. Microglia play an important role responding to injuries in the brain and a comprehensive understanding of the microglia-specific signaling during episodes of injury are pivotal for mitigating the damage induced by ICH. The three cofilin isoforms: actin binding protein, cofilin1 (cofilin) and cofilin2 are important regulators of F-actin turnover and reorganization and alterations in these processes can lead to neurodegenerative diseases. Cofilin rods/aggregates formed during pathological conditions play a crucial role in microglial activation, synaptic dysfunction and neuronal death. As a mechanistic proof of concept, targeting cofilin with siRNA or inhibitor in mice led to decreased hematoma volume, improved neurobehavioral functions and PSCI after experimental ICH. Immunofluorescence analysis of human autopsy ICH brain specimens also showed widespread cofilin activation in microglia in the perihematoma area. The novel findings support the scientific premise that cofilin signaling plays a key role in the secondary phase of ICH involving microglial activation and inflammation and subsequent PSCI and led us to hypothesize that inhibition of cofilin presents a novel therapeutic strategy. The proposed hypothesis will be addressed in three aims. Aim 1 will identify cofilin rods/aggregates and microglial activation in human ICH autopsy brain specimens by performing immunofluorescence. The spatiotemporal pattern of cofilin rods/aggregates and PSCI will be determined in wildtype (WT) mice over a protracted period of 60 days following ICH. Aim 2 will identify whether microglial or neuronal cofilin is mediating neuroinflammation and PSCI after ICH by using neuron and microglia-specific cofilin knockout mice. Aim 3 will study the therapeutic potential of a novel first of its class, cofilin inhibitor in aged WT mice subjected to ICH. The studies outlined in this proposal will provide insights on the role of cofilin signaling in ICH induced-microglial activation, inflammation and PSCI and the identification of potential therapeutic agents for drug discovery and development.