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Abstract Background Plasma gelsolin (pGSN) is an important part of the blood actin buffer that prevents negative consequences of possible F-actin deposition in the microcirculation and has various functions during host immune response. Recent reports reveal that severe COVID-19 correlates with reduced levels of pGSN. Therefore, using an in vitro system, we investigated whether pGSN could attenuate increased permeability of the blood–brain barrier (BBB) during its exposure to the portion of the SARS-CoV-2 spike protein containing the receptor binding domain (S1 subunit). Materials and methods Two- and three-dimensional models of the human BBB were constructed using the human cerebral microvascular endothelial cell line hCMEC/D3 and exposed to physiologically relevant shear stress to mimic perfusion in the central nervous system (CNS). Trans-endothelial electrical resistance (TEER) as well as immunostaining and Western blotting of tight junction (TJ) proteins assessed barrier integrity in the presence of the SARS-CoV-2 spike protein and pGSN. The IncuCyte Live Imaging system evaluated the motility of the endothelial cells. Magnetic bead-based ELISA was used to determine cytokine secretion. Additionally, quantitative real-time PCR (qRT-PCR) revealed gene expression of proteins from signaling pathways that are associated with the immune response. Results pGSN reversed S1-induced BBB permeability in both 2D and 3D BBB models in the presence of shear stress. BBB models exposed to pGSN also exhibited attenuated pro-inflammatory signaling pathways (PI3K, AKT, MAPK, NF-κB), reduced cytokine secretion (IL-6, IL-8, TNF-α), and increased expression of proteins that form intercellular TJ (ZO-1, occludin, claudin-5). Conclusion Due to its anti-inflammatory and protective effects on the brain endothelium, pGSN has the potential to be an alternative therapeutic target for patients with severe SARS-CoV-2 infection, especially those suffering neurological complications of COVID-19.
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Implementation and characterization of a physiologically relevant flow waveform in a 3D microfluidic model of the blood–brain barrier
Abstract Previous in vitro studies interrogating the endothelial response to physiologically relevant flow regimes require specialized pumps to deliver time‐dependent waveforms that imitate in vivo blood flow. The aim of this study is to create a low‐cost and broadly adaptable approach to mimic physiological flow, and then use this system to characterize the effect of flow separation on velocity and shear stress profiles in a three‐dimensional (3D) topology. The flow apparatus incorporates a programmable linear actuator that superposes oscillations on a constant mean flow driven by a peristaltic pump to emulate flow in the carotid artery. The flow is perfused through a 3D in vitro model of the blood–brain barrier designed to induce separated flow. Experimental flow patterns measured by microparticle image velocimetry and modeled by computational fluid dynamics reveal periodic changes in the instantaneous shear stress along the channel wall. Moreover, the time‐dependent flow causes periodic flow separation zones, resulting in variable reattachment points during the cycle. The effects of these complex flow regimes are assessed by evaluating the integrity of the in vitro blood–brain barrier model. Permeability assays and immunostaining for proteins associated with tight junctions reveal barrier breakdown in the region of disturbed flow. In conclusion, the flow system described here creates complex, physiologically relevant flow profiles that provide deeper insight into the fluid dynamics of separated flow and pave the way for future studies interrogating the cellular response to complex flow regimes.
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- Award ID(s):
- 1728239
- PAR ID:
- 10450868
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Biotechnology and Bioengineering
- Volume:
- 118
- Issue:
- 7
- ISSN:
- 0006-3592
- Format(s):
- Medium: X Size: p. 2411-2421
- Size(s):
- p. 2411-2421
- Sponsoring Org:
- National Science Foundation
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