Induction of Neuroinflammation and Neurotoxicity by Synthetic Hemozoin

Abstract

Hemozoin produced by Plasmodium falciparum during malaria infection has been linked to the neurological dysfunction in cerebral malaria. In this study, we determined whether a synthetic form of hemozoin (sHZ) produces neuroinflammation and neurotoxicity in cellular models. Incubation of BV-2 microglia with sHZ (200 and 400 µg/ml) induced significant elevation in the levels of TNFα, IL-6, IL-1β, NO/iNOS, phospho-p65, accompanied by an increase in DNA binding of NF-κB. Treatment of BV-2 microglia with sHZ increased protein levels of NLRP3 with accompanying increase in caspase-1 activity. In the presence of NF-κB inhibitor BAY11-7082 (10 µM), there was attenuation of sHZ-induced release of pro-inflammatory cytokines, NO/iNOS. In addition, increase in caspase-1/NLRP3 inflammasome activation was blocked by BAY11-7082. Pre-treatment with BAY11-7082 also reduced both phosphorylation and DNA binding of the p65 sub-unit. The NLRP3 inhibitor CRID3 (100 µM) did not prevent sHZ-induced release of TNFα and IL-6. However, production of IL-1β, NO/iNOS as well as caspase-1/NLRP3 activity was significantly reduced in the presence of CRID3. Incubation of differentiated neural progenitor (ReNcell VM) cells with sHZ resulted in a reduction in cell viability, accompanied by significant generation of cellular ROS and increased activity of caspase-6, while sHZ-induced neurotoxicity was prevented by N-acetylcysteine and Z-VEID-FMK. Taken together, this study shows that the synthetic form of hemozoin induces neuroinflammation through the activation of NF-κB and NLRP3 inflammasome. It is also proposed that sHZ induces ROS- and caspase-6-mediated neurotoxicity. These results have thrown more light on the actions of malarial hemozoin in the neurobiology of cerebral malaria.Electronic supplementary materialThe online version of this article (10.1007/s10571-019-00713-4) contains supplementary material, which is available to authorized users.

Inhibition of hemozoin-induced neuroinflammation by medicinal plants used for the treatment of malaria in Southwest Nigeria: implications for cerebral malaria

“…Hemozoin is known to induce in ammation and morphological changes in microvascular endothelium (Medana and Turner 2006;Prato et al 2011), leading to an increase in blood brain barrier (BBB) permeability, neuroin ammation and neurological sequelae in survivors (Basilico et al 2003;Tripathi et al 2009). Similar to these reports, our investigations have revealed that a synthetic form of hemozoin is in fact able to induce neuroin ammation in BV-2 microglia (Velagapudi et al 2019). Consequently, reducing the CNS effects of hemozoin in CM is a potential adjunctive strategy in reducing the neurological outcomes of the disease.…”

SARS-CoV-2 Spike Glycoprotein S1 Induces Neuroinflammation in BV-2 Microglia

“…The Caspase-Glo® 1 Inflammasome Assay (Promega) was used to measure the activity of caspase-1 directly in live cells or culture supernatants [ 30 ]. BV-2 microglia were seeded out in a 24-well plate at a density of 4 × 10 4 cells/ml and stimulated with S1 (10 ng/ml, 50 ng/ml and 10 ng/ml) for 24 h. After incubation, cell culture supernatants were collected and mixed with an equal volume of Caspase-Glo® 1 reagent or Caspase-Glo® 1 reagent + YVAD-CHO (1 µM) in a 96-well plate.…”

SARS-CoV-2 spike glycoprotein S1 induces neuroinflammation in BV-2 microglia

“…The caspase-Glo ® 1 inflammasome assay (Promega) was used to measure the activity of caspase-1 directly in live cells or culture supernatants [30]. BV-2 microglia were seeded out in 24-well plate at a density of 4 × 10 4 cells/mL and stimulated with S1 glycoprotein (10, 50 and 10 ng/mL) for 24 h. After incubation, cell culture supernatants were collected and mixed with equal volume of Caspase-Glo ® 1 reagent or Caspase-Glo ® 1 reagent + YVAD-CHO (1 μM) in a 96-well plate.…”