Ducruet Laboratory

Laboratory Focus

Stroke is the fourth leading cause of death and the leading cause of disability worldwide, yet therapeutic options remain limited. The primary goal of our laboratory is to develop new therapies for ischemic stroke by elucidating the cellular and molecular mechanisms of brain injury. In particular, the group studies the complement cascade–a key innate immune pathway activated after cerebral ischemia. Complement proteins amplify post-stroke inflammation and vascular injury and may drive maladaptive synaptic pruning in the post-ischemic brain.

Therefore, our lab employs in vitro (neural and endothelial cell cultures under oxygen-glucose deprivation) and in vivo models (rodent stroke and brain injury models) to investigate these mechanisms. Access to human stroke specimens further allows bench-to-bedside translation. Through these complementary approaches, our team seeks to identify molecular targets for modulation to improve outcomes in human stroke and brain injury.

C3aR-Targeted Stroke Therapy (NIH R01 Project)

A major ongoing initiative is a 5-year NIH R01 on endothelial C3a receptor (C3aR) signaling in reperfused stroke. Drs. Ducruet and Ahmad generated a novel mouse line with C3aR selectively deleted in endothelial cells. Using this gene-edited model, they will compare reperfused stroke outcomes (with tPA) in C3aR-null versus wild-type mice.

The specific aims are to test whether C3aR deletion:

Preserves blood–brain barrier integrity (limiting inflammatory cell entry)
Reduces post-tPA bleeding, edema, and neurological deficits
Prevents excess synapse loss due to aberrant complement activity

By examining acute injury and long-term cognitive outcomes, this study seeks to link C3aR-driven inflammation with post-stroke neurodegeneration. If successful, this work could set the stage for trials of a drug blocking the receptor’s activity, potentially enabling safer reperfusion therapy for more patients.

tPA-Mediated Complement Activation in Ischemic Stroke

We have demonstrated that intravenous thrombolysis (tPA) triggers a novel plasmin-dependent pathway that generates the complement anaphylatoxin C3a in ischemic brain. In murine models of reperfused stroke, tPA treatment exacerbates hemorrhagic conversion and cerebral edema.

Significantly, pharmacologic blockade of the C3a receptor (C3aR) markedly suppresses these deleterious effects, suggesting that complement inhibition can mitigate reperfusion injury.

Complement-Dependent Synaptic Remodeling

Recent work examines how complement proteins drive synapse loss after stroke. Complement components (such as C1q and C3) are abnormally expressed near neuronal synapses in peri-infarct cortex, implicating the same pruning pathways that function in normal development.

We are defining how post-ischemic complement signaling recruits microglia to eliminate synapses, and whether this process contributes to long-term cognitive deficits. Understanding this synaptic complement mechanism may reveal new ways to preserve neural circuits during stroke recovery.

Nanoliposome-Based Neuroprotection

We are exploring phospholipid nanoliposomes as a novel therapeutic strategy with our collaborators at the Phoenix VA and Midwestern University. In a mouse model of middle cerebral artery occlusion (MCAO), treatment with cargo-free nanoliposomes (phosphatidylcholine/cholesterol/monosialoganglioside vesicles) significantly reduced infarct size. These nanoparticles also protected cultured neurons and brain endothelial cells from oxygen–glucose deprivation by inducing antioxidant defenses.

This work (presented at the AHA conference and published in Stroke) establishes liposomal drug carriers as candidate neuroprotectants and supports further preclinical development.

Methodologies and Translational Approaches

To pursue these projects, our lab integrates a range of modern techniques. In vitro studies use primary neuron and endothelial cultures (e.g., oxygen-glucose deprivation models) to dissect molecular pathways (complement activation, oxidative stress, etc.). In vivo, the team employs well-established rodent stroke models (e.g., transient MCAO with reperfusion, photothrombotic stroke, and bilateral carotid artery stenosis model of VCID). We use advanced neuroimaging (MRI) and quantitative histology to measure infarct/hematoma volume, edema, blood-brain barrier disruption, and synaptic markers.

The laboratory also uses transgenic and gene-editing tools: the new C3aR knockout mouse is a key example. In parallel, sophisticated drug delivery systems are tested, including targeted nanoparticles and liposomal formulations, to improve brain uptake of therapeutics. This multifaceted approach is inherently translational: Rodent model findings correlate with human pathology using access to patient tissue and clinical data.

Translational Goals

The ultimate objective of our research program is to translate laboratory discoveries into better treatments for patients with stroke. By illuminating how complement and inflammation drive secondary brain injury, the group aims to identify drug targets (e.g., C3aR) that can be safely modulated in humans.

The recent NIH R01 project exemplifies this path: Demonstrating that C3aR blockade limits reperfusion injury would directly support clinical trials of C3aR antagonists. Likewise, validating nanoliposome therapies in preclinical models could lead to early-phase testing of these approaches. In all cases, the vision is to expand the therapeutic window of reperfusion and to protect the injured brain. Interrupting maladaptive inflammation could set the stage for new drugs that allow more patients to benefit from reperfusion therapy while reducing harmful edema and hemorrhage.

Through rigorous basic and translational research, the Ducruet Lab seeks to improve patient outcomes in ischemic stroke and related cerebrovascular disorders.