Neuroprotective effects of an in vitro BBB permeable phenoxythiophene sulfonamide small molecule in glutamate-induced oxidative injury

NX210c drug candidate peptide strengthens mouse and human blood-brain barriers

BACKGROUND

Alterations of blood-brain barrier (BBB) and blood-spinal cord barrier have been documented in various animal models of neurodegenerative diseases and in patients. Correlations of these alterations with functional deficits suggest that repairing barriers integrity may represent a disease-modifying approach to prevent neuroinflammation and neurodegeneration induced by the extravasation of blood components into the parenchyma. Here, we screened the effect of a subcommissural organ-spondin-derived peptide (NX210c), known to promote functional recovery in several models of neurological disorders, on BBB integrity in vitro and in vivo.

METHODS

In vitro, bEnd.3 endothelial cell (EC) monolayers and two different primary human BBB models containing EC, astrocytes and pericytes, in static and microfluidic conditions, were treated with NX210c (1-100 µM), or its vehicle, for 4 h and up to 5 days. Tight junction (TJ) protein levels, permeability to dextrans and transendothelial electrical resistance (TEER) were evaluated. In vivo, young and old mice (3- and 21-month-old, respectively) were treated daily intraperitoneally with NX210c at 10 mg/kg or its vehicle for 5 days and their brains collected at day 6 to measure TJ protein levels by immunohistochemistry.

RESULTS

NX210c induced an increase in claudin-5 protein expression after 24-h and 72-h treatments in mouse EC. Occludin level was also increased after a 24-h treatment. Accordingly, NX210c decreased by half the permeability of EC to a 40-kDa FITC-dextran and increased TEER. In the human static BBB model, NX210c increased by ∼ 25% the TEER from 3 to 5 days. NX210c also increased TEER in the human 3D dynamic BBB model after 4 h, which was associated with a reduced permeability to a 4-kDa FITC-dextran. In line with in vitro results, after only 5 days of daily treatments in mice, NX210c restored aging-induced reduction of claudin-5 and occludin levels in the hippocampus, and also in the cortex for occludin.

CONCLUSIONS

In summary, we have gathered preclinical data showing the capacity of NX210c to strengthen BBB integrity. Through this property, NX210c holds great promises of being a disease-modifying treatment for several neurological disorders with high unmet medical needs.

Effects of Sodium Nitroprusside on Lipopolysaccharide-Induced Inflammation and Disruption of Blood-Brain Barrier

In various neurodegenerative conditions, inflammation plays a significant role in disrupting the blood-brain barrier (BBB), contributing to disease progression. Nitric oxide (NO) emerges as a central regulator of vascular function, with a dual role in inflammation, acting as both a pro- and anti-inflammatory molecule. This study investigates the effects of the NO donor sodium nitroprusside (SNP) in protecting the BBB from lipopolysaccharide (LPS)-induced inflammation, using bEnd.3 endothelial cells as a model system. Additionally, Raw 264.7 macrophages were employed to assess the effects of LPS and SNP on their adhesion to a bEnd.3 cell monolayer. Our results show that LPS treatment induces oxidative stress, activates the JAK2/STAT3 pathway, and increases pro-inflammatory markers. SNP administration effectively mitigates ROS production and IL-6 expression, suggesting a potential anti-inflammatory role. However, SNP did not significantly alter the adhesion of Raw 264.7 cells to bEnd.3 cells induced by LPS, probably because it did not have any effect on ICAM-1 expression, although it reduced VCAM expression. Moreover, SNP did not prevent BBB disruption. This research provides new insights into the role of NO in BBB disruption induced by inflammation.

B355252 Suppresses LPS-Induced Neuroinflammation in the Mouse Brain

B355252 is a small molecular compound known for potentiating neural growth factor and protecting against neuronal cell death induced by glutamate in vitro and cerebral ischemia in vivo. However, its other biological functions remain unclear. This study aims to investigate whether B355252 suppresses neuroinflammatory responses and cell death in the brain. C57BL/6j mice were intraperitoneally injected with a single dosage of lipopolysaccharide (LPS, 1 mg/kg) to induce inflammation. B355252 (1 mg/kg) intervention was started two days prior to the LPS injection. The animal behavioral changes were assessed pre- and post-LPS injections. The animal brains were harvested at 4 and 24 h post-LPS injection, and histological, biochemical, and cytokine array outcomes were examined. Results showed that B355252 improved LPS-induced behavioral deterioration, mitigated brain tissue damage, and suppressed the activation of microglial and astrocytes. Furthermore, B355252 reduced the protein levels of key pyroptotic markers TLR4, NLRP3, and caspase-1 and inhibited the LPS-induced increases in IL-1β, IL-18, and cytokines. In conclusion, B355252 demonstrates a potent anti-neuroinflammatory effect in vivo, suggesting that its potential therapeutic value warrants further investigation.

Piceatannol Protects Brain Endothelial Cell Line (bEnd.3) against Lipopolysaccharide-Induced Inflammation and Oxidative Stress

Dysfunction of the blood-brain barrier (BBB) is involved in the pathogenesis of many cerebral diseases. Oxidative stress and inflammation are contributing factors for BBB injury. Piceatannol, a natural ingredient found in various plants, such as grapes, white tea, and passion fruit, plays an important role in antioxidant and anti-inflammatory responses. In this study, we examined the protective effects of piceatannol on lipopolysaccharide (LPS) insult in mouse brain endothelial cell line (bEnd.3) cells and the underlying mechanisms. The results showed that piceatannol mitigated the upregulated expression of adhesion molecules (ICAM-1 and VCAM-1) and iNOS in LPS-treated bEnd.3 cells. Moreover, piceatannol prevented the generation of reactive oxygen species in bEnd.3 cells stimulated with LPS. Mechanism investigations suggested that piceatannol inhibited NF-κB and MAPK activation. Taken together, these observations suggest that piceatannol reduces inflammation and oxidative stress through inactivating the NF-κB and MAPK signaling pathways on cerebral endothelial cells in vitro.