Neuroprotective Engineering Based on Innate Responses to Stroke

Northwestern University, Evanston IL

Investigators

Abstract

PI: Liu, Shu Q. Proposal Number: 1403036 Institution: Northwestern University Title: Neuroprotective Engineering Based on Innate Responses to Stroke Stroke is a prevalent disorder commonly caused by arterial plaques that block blood flow to the brain, resulting in brain injury, depression, mental retardation, and/or paralysis. The injured brain is often associated with bone-like structure formation, known as brain calcification, a process disrupting the brain structure and intensifying brain injury. To date, it remains poorly understood how stroke causes brain calcification and there are few approaches effective for prevention of brain calcification. In this application, the investigators intend to elucidate the role of a cell membrane-associated family of calcium-carrying molecules known as annexins in the induction of brain calcification in a mouse model of stroke. These molecules may move from the cell membrane to the intracellular contractile filaments when brain cells are injured to cause calcium deposition or calcification, as these molecules carry calcium ions. The investigators have discovered a liver-produced molecule known as trefoil factor 3 that potentially protects the injured brain from calcification by blocking annexin deposition. The significance of this discovery is that trefoil factor 3 may be potentially used as a drug to prevent brain calcification and injury in patients with stroke. In this project, the investigators will develop an engineering strategy for boosting trefoil factor 3 production in a mouse model of stroke by delivery of the trefoil factor 3 gene or protein and test the efficacy of the engineering approach for brain protection against annexin-dependent calcification. If successful, trefoil factor 3 can be produced by a biotechnology approach and applied to human patients with stroke to prevent brain calcification, thereby reducing brain injury and functional deficits. This effort may potentially lead to a reduction in stroke-induced human morbidity and mortality. In addition to these scientific aspects, the investigators will devote efforts to establish a new undergraduate education model integrating independent research into lecture topics. This form of education will allow students to understand scientific concepts from hands-on experience and to be more engaged in cutting-edge research, enhancing students creativity and capability of solving real-world problems. Cerebral ischemia or ischemic stroke is a prevalent disorder commonly caused by cerebral artery thrombosis and/or atherosclerosis, resulting in cerebral injury and neurological deficits including depression, mental retardation, and/or paralysis. Ischemic stroke is often associated with cerebral calcification or hydroxyapatite deposition, a process disrupting neuronal structure and intensifying cerebral injury. To date, the mechanisms of cerebral calcification remain elusive and few approaches have been established for protecting the cerebrum from calcification. The investigators have found that a cell membrane-associated family of calcium-carrying molecules known as annexins may translocate from the cell membrane to the cytoskeletal microfilaments in ischemic neurons to facilitate hydroxyapatite formation. Furthermore, a liver-produced endocrine molecule known as trefoil factor 3 (TFF3) is upregulated in response to stroke, potentially protecting the ischemic cerebrum from calcification by blocking annexin deposition. In the proposed research, the investigators intend to achieve three aims: (1) evaluate the role of annexins A2, A3, and A5 in ischemic cerebral calcification and injury; (2) assess the role of TFF3 in protection of the ischemic cerebrum from annexin-dependent calcification and injury; and (3) establish neuroprotective engineering strategies based on the mechanisms of TFF3 action for maximizing protection against cerebral calcification in stroke. In a mouse model of ischemic stroke, the role of annexins will be evaluated by using siRNA-mediated loss-of-annexin and recombinant annexin-based gain-of-annexin approaches; the anti-calcification role of TFF3 will be tested by using a TFF3-/- mouse model with or without recombinant TFF3 administration; and the role of TFF3 in interference with annexin binding to neuronal micro-filaments will be assessed by molecular binding assays in the presence or absence of TFF3. Protective engineering approaches will be established based on TFF3 gene transfection and controlled TFF3 protein delivery technologies to boost TFF3 expression following ischemic stroke. These investigations will provide a foundation for understanding the mechanisms of ischemic cerebral calcification and establishing engineering technologies for protection against ischemic cerebral calcification and injury, thus potentially reducing stroke-induced human morbidity and mortality.