Role of the Redox State of Human Peroxiredoxin-5 on Its TLR4-Activating DAMP Function

Abstract

Human peroxiredoxin-5 (PRDX5) is a unique redox-sensitive protein that plays a dual role in brain ischemia-reperfusion injury. While intracellular PRDX5 has been reported to act as a neuroprotective antioxidative enzyme by scavenging peroxides, once released extracellularly from necrotic brain cells, the protein aggravates neural cell death by inducing expression of proinflammatory cytokines in macrophages through activation of Toll-like receptor (TLR) 2 (TLR2) and 4 (TLR4). Although recent evidence showed that PRDX5 was able to interact directly with TLR4, little is known regarding the role of the cysteine redox state of PRDX5 on its DAMP function. To gain insights into the role of PRDX5 redox-active cysteine residues in the TLR4-dependent proinflammatory activity of the protein, we used a recombinant human PRDX5 in the disulfide (oxidized) form and a mutant version lacking the peroxidatic cysteine, as well as chemically reduced and hyperoxidized PRDX5 proteins. We first analyzed the oxidation state and oligomerization profile by Western blot, mass spectrometry, and SEC-MALS. Using ELISA, we demonstrate that the disulfide bridge between the enzymatic cysteines is required to allow improved TLR4-dependent IL-8 secretion. Moreover, single-molecule force spectroscopy experiments revealed that TLR4 alone is not sufficient to discriminate the different PRDX5 redox forms. Finally, flow cytometry binding assays show that disulfide PRDX5 has a higher propensity to bind to the surface of living TLR4-expressing cells than the mutant protein. Taken together, these results demonstrate the importance of the redox state of PRDX5 cysteine residues on TLR4-induced inflammation.

Roles of Exosomes in Chronic Rhinosinusitis: A Systematic Review

“…The authors validated this proteomic data set by performing Western blots on independent samples of tissue and exosomes in the CRSwNP and HS groups and confirmed that CST-1, PRDX5, and GP6 were significantly differentially expressed in both tissue and exosomes among the CRSwNP group relative to HS group [ 15 ]. Peroxiredoxin-5 (PRDX5) might trigger a proinflammatory response by inducing the expression of proinflammatory cytokines in macrophages through activation of Toll-like receptors [ 111 , 112 ]. The activation of toll-like receptor 4 (TLR4) is important for initiating allergic inflammation and antifungal immunity [ 113 ].…”

Machine learning and deep learning to identifying subarachnoid haemorrhage macrophage‐associated biomarkers by bulk and single‐cell sequencing

“…41 PRDX5, involved in redox balance during brain ischemia-reperfusion, presents a dual role; intracellularly exerting neuroprotective effects and extracellularly inducing pro-inflammatory responses. 42 In conclusion, CD14, GPNMB, SPP1, PRDX5 and macrophages stand central in orchestrating inflammatory responses, tissue repair and neuroprotection in SAH. Further exploration of their interaction mechanisms, regulatory roles in macrophage activation and crosstalk with signalling pathways will deepen our understanding of SAH pathogenesis, paving the way for innovative therapeutic strategies.…”

“…Its neuroprotective effects, counterbalanced by potential contributions to chronic hydrocephalus underscore the need for nuanced investigations 41 . PRDX5, involved in redox balance during brain ischemia–reperfusion, presents a dual role; intracellularly exerting neuroprotective effects and extracellularly inducing pro‐inflammatory responses 42 …”

Zearalenone exposure differentially affects the ovarian proteome in pre-pubertal gilts during thermal neutral and heat stress conditions

“…The AKR7A2 protein detoxifies aldehydes and ketones and catalyzes the reduction of xenobiotics ( Barski et al, 2008 ) and is increased by ZEN exposure in both TN groups but decreased in HS gilt ovaries. Similar to PRDX4 which was altered in TN gilts exposed to ZEN, PRDX5 responds to oxidative stress and induces proinflammatory cytokines in macrophages through activation of toll-like receptor 4 ( Poncin et al, 2021 ). Both TN and PF had reduced levels of PRDX5 while HS gilts had higher PRDX5 in response to ZEN.…”