Deciphering the Molecular Basis of Blood-Brain Barrier Disruption and Cognitive Decline in NPSLE

 

Deciphering the Molecular Basis of Blood-Brain Barrier Disruption and Cognitive Decline in NPSLE

 

Leads: Sanju S, Dr. Anto Sam Crosslee

Team Members: Kamala Vanarsa, Vinaika Maruvada, Shalaka Shekhar Dhavalikar, Madeline C Rogers, Jeremy John, Angela Nguyen, Harini Venkatesh

Collaborators: Dr. John Hanly, Dr. Alexandra Legge, Dr. Zahi Touma

Project Summary:

Neuropsychiatric systemic lupus erythematosus (NPSLE) represents a severe complication of systemic lupus erythematosus (SLE), impacting both the central and peripheral nervous systems. This study explores the molecular mechanisms that lead to the breakdown of the blood-brain barrier (BBB) in NPSLE. We employ high sensitivity, multiplexed O-link PEA platform to detect dysregulated proteins in serum of NPSLE patients. By introducing these candidate biomarkers to in-house developed in vitro BBB model, we aim to isolate specific signaling molecules and pathways that precipitate BBB disruption and can cause cognitive decline in NPSLE patients. The project integrates high-resolution microscopy, proteomic profiling, gene expression analysis and co-culture techniques to map the trajectory from molecular alterations to functional barrier failure.

What is already known in the field?

The clinical presentation of NPSLE is highly diverse encompassing both diffuse and focal manifestations. Clinical research confirms that Blood-Brain Barrier (BBB) disruption is considered a crucial, though sometimes controversial, feature in the pathogenesis of NPSLE. This highly selective barrier normally protects the brain; however, its failure permits the infiltration of autoantibodies and inflammatory mediators into the brain parenchyma. This increase in permeability or ‘leakiness’ in the BBB is believed to be the primary mechanism transitioning systemic inflammation to neuroinflammation, thereby contributing to neuronal and synaptic toxicity that results in cognitive impairment.

What is new?

Although the significance of the BBB is recognized, the exact triggers of its dysfunction in NPSLE remains poorly understood. This project introduces several novel elements:

  • Elucidating the role of specific proteins: We are testing the effects of specific proteins recently identified by our lab to be dysregulated in NPSLE body fluids.
  • Comprehensive Molecular Mapping: We are also conducting quantitative proteomic and gene expression analyses specifically targeting junction proteins to pinpoint exactly which “structural anchors” of the barrier are disrupted.
  • Integrative Modeling: By combining in vitro functional assays and proteomic studies with patient samples, we are developing a representation of the NPSLE disease state that is more accurate than traditional models.

Why is this important?

Elucidating the mechanisms underlying BBB breach is essential for improving patient outcomes.

  • Biomarker Discovery: The candidate proteins identified could serve as diagnostic or prognostic biomarkers, helping clinicians identify NPSLE earlier or predict disease progression or treatment response.
  • Targeted Therapies: Identifying the proteins responsible for barrier breakdown facilitates the development of therapies designed to restore BBB integrity and prevent neurological damage.
  • Reducing Disability: By halting the influx of neurotoxic substances into the brain, we can potentially mitigate the debilitating cognitive decline associated with this condition.

Ongoing and future steps

  • Model Validation: We are currently characterizing the in vitro BBB model by assessing permeability to tracer molecules, verifying the localization of junction proteins and employing Transendothelial Electrical Resistance (TEER) to non-invasively quantify the tightness and integrity of the BBB.
  • Patient Sample Correlation: Concurrently, multiplex proteomic assays are being utilized to identify candidate biomarkers associated with BBB disruption and cognitive decline in patient samples.
  • Factor Testing: The in vitro model is being treated with NPSLE-specific cytokines and proteins to observe real-time changes in endothelial cell tight junction proteins and gene expression.
  • In vivo Validation: We aim to test the ability of selected proteins and antibodies to induce blood brain barrier breach in pre-clinical models.