The goal of this proposal is to develop new treatment strategies for enhancing neuronal repair using nanobodies against danger signal receptors (e.g., P2X7). By targeting danger signals, we hope to modulate the stroke-induced sustained immune response, thereby improving functional recovery and neuronal plasticity.

We will particularly investigate the contribution of different inflammasome sensors for chronic neuroinflammation and test üharmacological approches for inhibition of inflammasome activation. Furthermore, we will analyze the non-immunological role of inflammasome in enruonal plasticity via localized cell death and dendrite retraction involved in post-stroke neuronal plasticity.

We will adopt complimentary approaches to deplete microglia either in timed intervals or chronically after stroke and will investigate the effect of microglial depletion on functional recovery. For this, we will combine multiple readouts for neuronal plasticity, beahvior and neuronal network function to comprehensively assess post-stroke recovery.

by investigating the following aims: AIM 1: Characterize the effects of microglia on microvascular integrity and post-stroke angiogenesis, AIM2: Characterize the effects of T cells on post-stroke microvascular remodeling, AIM 3: Identify molecular targets of inflammation-mediated microvascular remodeling

We will use readily available transgenic mouse strains carrying mutations in the KKS, or pharmacological inhibitors interfering with the KKS, and mice with selective defects in different immune cell subpopulations. In these animals stroke will be induced and long-term functional recovery, neuronal plasticity and angiogenesis will be analyzed.

For this purpose we will analyze the effect of exercise on T cell localization in ischemic brain and on the functional and molecular phenotype of T cells as well as the T cell-mediated exercise effects on neuronal plasticity, i.e. axonal sprouting and neuronal excitability.  Overall, we aim to provide the basis for future recovery-enhancing therapies that modulate identified molecular targets – so called exercise mimetics.

To identify key molecular mechanisms underlying neuronal cell death in early stages we will use mice transgenic for a bacterial artificial chromosome (BAC) that encodes the EGFP-tagged ribosomal protein L10a driven by a cell-specific promoter. Using the transgenic mouse line Glt25d2 bacTRAP will allow us to affinity purify polysomal mRNAs (translatome) specifically from cortical layer V neurons following stroke. To identify neuroregenerative pathways in the neuronal translatome that are driven by T cells or microglia we will selectively deplete CD4 cells, CD8 cells or microglia.

This project will address immunometabolism as potential driver of immune-mediated neuronal damage, and purinergic signaling as a potential mechanism underlying stroke-induced immune suppression. These properties will be analysed in a prospectively acquired bicentric cohort of patients with ischemic stroke at different time points.

to (1) define the characteristics and determinants of microglia activation after human stroke; (2) correlate microglial activation with the profile of inflammatory markers and circulating immune cells; (3) correlate microglial activation with infarct evolution, secondary neurodegeneration, and stroke outcome; and (4) develop criteria for selecting patients for future immune intervention trials. We will further compare the characteristics of microglial activation patterns in human stroke with those of experimental stroke in mice.

This will be achieved by first defining the most appropriate lesion models and outcome parameters to study stroke recovery, then define SOPs for these techniques, train collaborating laboratories of the research groups on these SOPs and finally prepare the infrastructure for a preclinical multicenter RCT. Additionally, this core project will provide a pre-publication cross-check of experimental in vivo methodology and coordinate an internal peer review of manuscript reporting results of the research group.