Cobalt Chloride-induced Hypoxia Ameliorates NLRP3-Mediated Caspase-1 Activation in Mixed Glial Cultures

Abstract

Hypoxia has been shown to promote inflammation, including the release of proinflammatory cytokines, but it is poorly investigated how hypoxia directly affects inflammasome signaling pathways. To explore whether hypoxic stress modulates inflammasome activity, we examined the effect of cobalt chloride (CoCl2)-induced hypoxia on caspase-1 activation in primary mixed glial cultures of the neonatal mouse brain. Unexpectedly, hypoxia induced by oxygen-glucose deprivation or CoCl2 treatment failed to activate caspase-1 in microglial BV-2 cells and primary mixed glial cultures. Of particular interest, CoCl2-induced hypoxic condition considerably inhibited NLRP3-dependent caspase-1 activation in mixed glial cells, but not in bone marrow-derived macrophages. CoCl2-mediated inhibition of NLRP3 inflammasome activity was also observed in the isolated brain microglial cells, but CoCl2 did not affect poly dA:dT-triggered AIM2 inflammasome activity in mixed glial cells. Our results collectively demonstrate that CoCl2-induced hypoxia may negatively regulate NLRP3 inflammasome signaling in brain glial cells, but its physiological significance remains to be determined.

Curcumin inhibits cobalt chloride-induced epithelial-to-mesenchymal transition associated with interference with TGF-β/Smad signaling in hepatocytes

“…17,18 In the current study, we established hypoxia-induced EMT in hepatocytes Curcumin inhibits EMT in human hepatocytes D Kong et al treated with CoCl 2 in culture, because this chemical has been widely reported to be a hypoxia-mimicking agent blocking aerobic respiration and mitochondrial biogenesis within cells. [11][12][13] Herein, the occurrence of EMT could be confirmed by the significant morphological changes and increased expression of mesenchymal makers α-SMA, vimentin, N-cadherin, fibronectin, and Snail in hepatocytes exposed to CoCl 2 at doses without cytotoxicity in culture. Our results are also in line with a recent study demonstrating that exposure of primary mouse hepatocytes to 1% oxygen stimulated them to undergo EMT by activating hypoxia inducible factor-1α.…”

“…[11][12][13] We aimed to establish an EMT model induced by CoCl 2 -mediated hypoxia in hepatocytes. We initially performed MTT assay to determine the dose range for CoCl 2 not affecting hepatocyte proliferation.…”

Inflammasome Priming in Sterile Inflammatory Disease

“…The authors propose, but do not confirm, a role for ROS in such hypoxia-regulated priming. By contrast, CoCl2 was observed to have the opposite effect in mouse mixed glial cells [26] .…”

25-hydroxycholesterol contributes to cerebral inflammation of X-linked adrenoleukodystrophy through activation of the NLRP3 inflammasome

“…THP-1 cells were differentiated into macrophage-like cells using a phorbol 12-myristate 13-acetate treatment and cultured in RPMI-1640 supplemented with 10% FBS, 2 mM glutamine, 10 mM HEPES, 1 mM sodium pyruvate, 0.05 mM 2-mercaptoethanol and antibiotics56. Mouse brain mixed glial cells were isolated from the whole brain of pups on the first postnatal day and cultured in DMEM/F-12 medium for 3 weeks as described previously57. Microglial cells were further enriched from the mixed glial cultures by mild trypsinization58.…”