Dimethyl fumarate reduces TNF and Plasmodium falciparum induced brain endothelium activation in vitro

Abstract

Background Cerebral malaria (CM) is associated with morbidity and mortality despite the use of potent anti-malarial agents. Brain endothelial cell activation and dysfunction from oxidative and inflammatory host responses and products released by Plasmodium falciparum-infected erythrocytes (IE), are likely the major contributors to the encephalopathy, seizures, and brain swelling that are associated with CM. The development of adjunctive therapy to reduce the pathological consequences of host response pathways could improve outcomes. A potentially protective role of the nuclear factor E2-related factor 2 (NRF2) pathway, which serves as a therapeutic target in brain microvascular diseases and central nervous system (CNS) inflammatory diseases such as multiple sclerosis was tested to protect endothelial cells in an in vitro culture system subjected to tumour necrosis factor (TNF) or infected red blood cell exposure. NRF2 is a transcription factor that mediates anti-oxidant and anti-inflammatory responses. Methods To accurately reflect clinically relevant parasite biology a unique panel of parasite isolates derived from patients with stringently defined CM was developed. The effect of TNF and these parasite lines on primary human brain microvascular endothelial cell (HBMVEC) activation in an in vitro co-culture model was tested. HBMVEC activation was measured by cellular release of IL6 and nuclear translocation of NFκB. The transcriptional and functional effects of dimethyl fumarate (DMF), an FDA approved drug which induces the NRF2 pathway, on host and parasite induced HBMVEC activation was characterized. In addition, the effect of DMF on parasite binding to TNF stimulated HBMVEC in a semi-static binding assay was examined. Results Transcriptional profiling demonstrates that DMF upregulates the NRF2-Mediated Oxidative Stress Response, ErbB4 Signaling Pathway, Peroxisome Proliferator-activated Receptor (PPAR) Signaling and downregulates iNOS Signaling and the Neuroinflammation Signaling Pathway on TNF activated HBMVEC. The parasite lines derived from eight paediatric CM patients demonstrated increased binding to TNF activated HBMVEC and varied in their binding and activation of HBMVEC. Overall DMF reduced both TNF and CM derived parasite activation of HBMVEC. Conclusions These findings provide evidence that targeting the NRF2 pathway in TNF and parasite activated HBMVEC mediates multiple protective pathways and may represent a novel adjunctive therapy to improve infection outcomes in CM.

Plasmodium falciparum and TNF-α Differentially Regulate Inflammatory and Barrier Integrity Pathways in Human Brain Endothelial Cells

“…TNF-α activation of the endothelium induces the secretion of inflammatory cytokines and chemokines, along with the increase in surface leukocyte adhesion molecules ( 13 , 36 ). The RNA-seq analysis revealed that upregulation of specific inflammatory response pathways is induced by both TNF-α and P. falciparum -iRBCLs ( Fig.…”

Cerebral malaria – modelling interactions at the blood–brain barrier in vitro

“…In malaria research, this method has been used to investigate how parasite-derived products or iRBC binding affect barrier integrity. This was done by co-incubating endothelial cells in the upper chamber with P. falciparum isolates or recombinant proteins ( Avril et al, 2019 ; Gillrie et al, 2012 ; Jambou et al, 2010 ; Mita-Mendoza et al, 2020 ; Moxon et al, 2020 ; Oggungwan et al, 2018 ; Thongdee and Na-Bangchang, 2017 ; Tripathi et al, 2007 ). Kinetic studies that follow the disruption and repair of barrier integrity over time in response to P. falciparum exposure ( Avril et al, 2019 ; Gillrie et al, 2016 ) or those that measure the efficacy of compounds designed to rescue barrier integrity ( Liu et al, 2018 ; Storm et al, 2020 ) can also be investigated using the Boyden chamber method.…”

Diffraction contrast in cryo-scanning transmission electron tomography reveals the boundary of hemozoin crystals in situ

“…2 Even when CM improves upon treatment with potent antimalarial drugs, survivors can experience debilitating aer-effects such as seizures and neurocognitive decits, especially in pediatric patients. [2][3][4] Within the human host, aer a brief asymptomatic phase within liver cells, P. falciparum parasites infect and thrive within red blood cells (RBC), giving rise to the clinical phase of malaria. The life cycle within the infected RBC (iRBC) lasts for about 48 hours (intraerythrocytic developmental cycle or IDC).…”