Docosanoids modulate homeostasis and cell survival after ischemic stroke

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PROJECT SUMMARY / ABSTRACT Although neuroprotective strategies have shown promise, no treatment has demonstrated efficacy after stroke. This project focuses on the neuroprotective bioactivity of docosanoid (DOC) mediators: Neuroprotectin D1 (NPD1), Resolvin D1 (RvD1), and their combination (NPD1+RvD1) against ischemic and embolic experimental stroke. These lipid mediators are biosynthesized “on demand” in response to the onset of stroke to resolve neuroinflammation and restore homeostasis. Our preliminary studies show that administration of NPD1 after OGD in neuronal cell cultures modifies clusters of genes and upstream potential master regulators that decrease neuronal apoptosis and neuroinflammation, improve cell homeostasis, and that beneficially impact genes expressed in ischemia-reperfusion. In addition, we show that DOC provide neurological/behavioral recovery, reduce infarct size, increase neurogenesis, and promote cell survival after ischemic stroke. The overall goal of our studies is to uncover a mechanistic understanding of DOC action in MCAo. Our central hypothesis is that DOC foster neuronal and astrocyte integrity by targeting selective gene clusters preceding neuronal protection and by the homeostatic signaling integration regulated by the mesencephalic astrocyte-derived neurotrophic factor (MANF) and by the ring finger protein 146 (Iduna). Specific aim 1 will test the hypothesis that DOC regulate pro-homeostatic and cell survival bioactivity after MCAo by modulating specific gene clusters. We will define the doses and therapeutic window, as well as their effect on the ischemic penumbra and we will define whether the lipid mediators are neuroprotective in embolic stroke with or without tissue plasminogen activator of thrombolysis. We selected genes from our data on neuronal cultures, including, some encoding lncRNAs, and propose to define by RT-qPCR high-throughput microfluidics workflow their expression after MCAo with and without DOC. Specific aim 2 will test the hypothesis that MANF and Iduna enhanced abundance by DOC integrates homeostatic signaling restoration and proliferation of neural stem cells leading to neuroprotection. Both are pro- survival proteins that target different neuroprotective mechanisms. Since NPD1 biosynthesis is stimulated by neurotrophins, we will explore the relationship DHA→DOC (NPD1, RvD1 and NPD1+RvD1) →MANF→Iduna→ protection by unfolded protein response pro-survival signaling outputs. A DOC or combinations will outline outputs of the unfolded protein response driven by MANF and Iduna. Since ischemic stroke engages UPR signaling we will define lncRNAs as regulators and effectors of UPR that fine-tune the output of the stress signaling pathways and identify also which specific gene signatures are MANF and or Iduna dependent. The scientific premise of the proposed studies is that identification of the most effective DOC or combination of DOC to target gene clusters necessary for neuroprotection/neurorestoration modulated by the lipid mediators which will provide the basis for future clinical studies on potential interventions to reduce the immediate and long-term consequences of stroke.