Stroke is among the leading causes of mortality worldwide, yet the mechanisms underlying its pathophysiology are not fully understood. Our laboratory has found a novel gene, Botch, which confers protection from cell death in models of ischemia, and also regulates the proliferation and differentiation of neural precursor cells. Botch was identified from a functional screen for neuroprotective genes, and is upregulated by ischemic preconditioning. Futhermore, expression of the gene confers protection from oxygen glucose deprivation (OGD) and NMDA excitotoxicity in primary cortical neuron cultures. The gene is expressed during various stages of development in multiple organs including the brain and cardiovascular system. Previous data generated in our laboratory show that Botch promotes both embryonic and adult neurogenesis in vivo and neuronal differentiation in vitro. Furthermore, Botch can bind to Notchi and Notch3 and inhibit Notch signaling, a pathway known to be involved in promoting neural precursor survival and regulating cellular differentiation. Our laboratory has developed tools to elucidate the function of Botch, including a knock-out (KO) mouse, constructs for gene overexpression and knockdown, and specific monoclonal and polyclonal antibodies. We have experience in immunohistochemisty and retrovirus labeling techniques to evaluate Botch-regulated neurogensis in vivo. Furthermore, our laboratory has expertise in a mouse model of stroke that employs focal cerebral ischemia. We propose that examining Botch's role on adult neurogenesis in the context of cerebral ischemia will further our understanding of underlying cellular and molecular processes that contribute to morbidity, with the ultimate goal of developing therapies to curtail the pathological outcome of stroke.
Aim 1 : The effect of Botch on adult neurogenesis. Does Botch influence neuronal differentiation and integration in vivo? We hypothesize that the Botch KO mouse will display increased rates of gliogenesis and a decreased functional integration of newborn neurons. Based on preliminary data, we hypothesize that Botch over- expression will lead to increased neuronal differentiation in vivo. Additionally, we hypothesize that in behavioral testing, the Botch KO mouse will exhibit a deficit in hippocampal-dependent spatial memory.
Aim 2 : What is Botch's impact on neurogenesis and cell death following stroke? We hypothesize that the Botch KO mouse will experience a greater severity of injury following stroke and disregulation of post-stroke neurogenesis and recovery.
|Chi, Zhikai; Byrne, Sean T; Dolinko, Andrew et al. (2014) Botch is a ?-glutamyl cyclotransferase that deglycinates and antagonizes Notch. Cell Rep 7:681-8|