p(HGNC:IL18)
IL-1β and IL-18 are synthesized as inactive precursors, proIL-1β and proIL-18, respectively, and require inflammasomes for their maturation PubMed:24561250
Activation of NLRP3 leads to the generation of interleukin-1b (IL-1b) and interleukin 18 (IL-18), which are being cleaved by caspase-1 from their inactive precursors and subsequently PubMed:28019679
Activation of NLRP3 leads to the generation of interleukin-1b (IL-1b) and interleukin 18 (IL-18), which are being cleaved by caspase-1 from their inactive precursors and subsequently PubMed:28019679
In addition, type I IFNs can reduce IL-1β and IL-18 release by functioning at two levels. PubMed:23702978
The transcription of pro-IL-1β is induced by the activation of the transcription factor nuclear factor-κB (NF-κB), whereas pro-IL-18 is constitutively expressed and its expression is increased after cellular activation. PubMed:23702978
Inflammasomes are key signalling platforms that detect pathogenic microorganisms and sterile stressors, and that activate the highly pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18. PubMed:23702978
Once the protein complexes have formed, the inflammasomes activate caspase 1, which proteolytically activates the pro-inflammatory cytokines interleukin-1β (IL-1β)3 and IL-18. PubMed:23702978
Active caspase 1 proteolytically activates a number of proteins8, including pro-IL-1β and pro-IL-18 (REFS 9,10), and induces their release via a non-classical secretion pathway11. PubMed:23702978
Active caspase 1 proteolytically activates a number of proteins8, including pro-IL-1β and pro-IL-18 (REFS 9,10), and induces their release via a non-classical secretion pathway11. PubMed:23702978
In addition, it was recently shown that CD95 signalling mediates IL-1β and IL-18 processing through the activation of caspase 8 (REF. 60) (FIG. 1). PubMed:23702978
Probenecid, an inhibitor of pannexin 1, has been shown to significantly inhibit the expression and activation of the NLRP2 inflammasome, and the maturation of bothIL-1β and IL-18 in human astrocytes induced by ATP (Minkiewicz et al., 2013) PubMed:24561250
Aging, another risk factor of AD, has been found to activate the NLRP1 inflammasome and upregulate IL-18 and IL-1β levels in the hippocampus of aged mice (Mawhinney et al., 2011) PubMed:24561250
Spinal cord injury causes IL-18 and IL-1β release from neuronal cells through the activation of the NLRP1 inflammasome, composed of receptor NLRP1, adaptor protein ASC, caspase-1, caspase-11 and X-linked inhibitor of apoptosis protein (de Rivero Vaccari et al., 2008) PubMed:24561250
Inflammasomes involve in the maturation of IL-1β and IL-18 are expressed in neurons (de Rivero Vaccari et al., 2008; Yang-Wei Fann et al., 2013; Zou and Crews, 2012) PubMed:24561250
Like IL-1β, in most cases, the mature secretable form of IL-18 is generated by caspase-1 through the activation of inflammasome PubMed:24561250
However the maturation of IL-18 and IL-1β could be regulated by the same type of inflammasome PubMed:24561250
Caspase-1 is the protease that cleaves the precursor of the proinflammatory molecules to form their mature form, such as IL-1β and IL-18 (Schroder and Tschopp, 2010) PubMed:24561250
Like IL-1β, in most cases, the mature secretable form of IL-18 is generated by caspase-1 through the activation of inflammasome PubMed:24561250
For example, down-regulation of NLRP1 in macrophages trigger by Cordyceps sinensis mycelium reduces both IL-18 and IL-1β levels (Huang et al., 2013) PubMed:24561250
ASC neutralization reduces the upregulation in IL-18 and IL-1β levels (de Rivero Vaccari et al., 2008) PubMed:24561250
In human astrocytes, ATP released from damaged or dying cells after traumatic brain injury activates the NLRP2 inflammasome, leading to the maturation of both IL-1β and IL-18 (Minkiewicz et al., 2013) PubMed:24561250
Probenecid, an inhibitor of pannexin 1, has been shown to significantly inhibit the expression and activation of the NLRP2 inflammasome, and the maturation of bothIL-1β and IL-18 in human astrocytes induced by ATP (Minkiewicz et al., 2013) PubMed:24561250
Interleukins, in particular IL-1β and IL-18, are upregulated in AD brain, and the overexpression of IL-1β or IL-18 is critical for the onset of the inflammatory process (Rubio-Perez and Morillas-Ruiz, 2012), and both mediate the expression of a vast array of inflammatory genes (Weber et al., 2010) PubMed:24561250
Spinal cord injury causes IL-18 and IL-1β release from neuronal cells through the activation of the NLRP1 inflammasome, composed of receptor NLRP1, adaptor protein ASC, caspase-1, caspase-11 and X-linked inhibitor of apoptosis protein (de Rivero Vaccari et al., 2008) PubMed:24561250
It is noteworthy that IL-1 beta and IL-18 can activate various cell types, par- ticularly astrocytes and microglia to induce additional cytokine release involving IL-1 beta , IL-6, and IL-18, and also nitric oxide (NO) synthase that can stimulate production of free radical NO, leading to the forma- tion of peroxynitrite that denatures DNA and impairs cellular energy pathways [48, 49]. PubMed:27314526
It is noteworthy that IL-1 beta and IL-18 can activate various cell types, par- ticularly astrocytes and microglia to induce additional cytokine release involving IL-1 beta , IL-6, and IL-18, and also nitric oxide (NO) synthase that can stimulate production of free radical NO, leading to the forma- tion of peroxynitrite that denatures DNA and impairs cellular energy pathways [48, 49]. PubMed:27314526
Inflammasomes are responsible for the maturation of pro-inflammatory cytokines such as interleukin (IL)-1beta, IL-18, and IL-33 and activation of inflammatory cell death, pyroptosis. PubMed:27314526
Post activation of the inflammasome, caspase 1 enzyme initiates the maturation of pro-inflammatory cytokines particularly interleukin (IL)-1beta, IL-18, and IL-33 [4] (Fig. 1),and inflammation mediated cell death occurs via the nucleotide-binding domain and leucine-rich repeat(NLR) family of proteins [5]. PubMed:27314526
In AD, microglial cells and astrocytes express NLRP3, which in turn can detect A beta plaques and act by secreting caspase-1 to activate IL-1 beta and IL- 18 [23–25]. PubMed:27314526
Both IL-1 beta and IL-18 are generated in their mature secreted form by caspase-1 through activa- tion of the inflammasome. PubMed:27314526
Once activated, caspase-1 promotes the maturation of the proin- flammatory cytokines IL-1 beta , IL-18, and IL-33. PubMed:27314526
However, IL- 18 can be derived as a byproduct from the activities of various extracellular enzymes such as protease 3, serine protease, elastase and cathepsin G [62–65]. PubMed:27314526
However, IL- 18 can be derived as a byproduct from the activities of various extracellular enzymes such as protease 3, serine protease, elastase and cathepsin G [62–65]. PubMed:27314526
However, IL- 18 can be derived as a byproduct from the activities of various extracellular enzymes such as protease 3, serine protease, elastase and cathepsin G [62–65]. PubMed:27314526
Increased levels of IL-1 beta and IL-18 have been detected in serum, cerebrospinal fluid, and brains of patients with AD and in other forms of dementia [42–46]. PubMed:27314526
Both these studies indicated an important role of IL-18 in AD. PubMed:27314526
Increased levels of IL-1 beta and IL-18 have been detected in serum, cerebrospinal fluid, and brains of patients with AD and in other forms of dementia [42–46]. PubMed:27314526
TNF-α [27], IL-1β [28], IL-18 [29], CXCL10 [30] and TGF-β1 [31] are known to be elevated in the AD brain. PubMed:27288790
Inflammasomes involve in the maturation of IL-1β and IL-18 are expressed in neurons (de Rivero Vaccari et al., 2008; Yang-Wei Fann et al., 2013; Zou and Crews, 2012) PubMed:24561250
Interleukins, in particular IL-1β and IL-18, are upregulated in AD brain, and the overexpression of IL-1β or IL-18 is critical for the onset of the inflammatory process (Rubio-Perez and Morillas-Ruiz, 2012), and both mediate the expression of a vast array of inflammatory genes (Weber et al., 2010) PubMed:24561250
Interleukins, in particular IL-1β and IL-18, are upregulated in AD brain, and the overexpression of IL-1β or IL-18 is critical for the onset of the inflammatory process (Rubio-Perez and Morillas-Ruiz, 2012), and both mediate the expression of a vast array of inflammatory genes (Weber et al., 2010) PubMed:24561250
Increased levels of IL-1 beta and IL-18 have been detected in serum, cerebrospinal fluid, and brains of patients with AD and in other forms of dementia [42–46]. PubMed:27314526
Both these studies indicated an important role of IL-18 in AD. PubMed:27314526
Increased levels of IL-1 beta and IL-18 have been detected in serum, cerebrospinal fluid, and brains of patients with AD and in other forms of dementia [42–46]. PubMed:27314526
It is noteworthy that IL-1 beta and IL-18 can activate various cell types, par- ticularly astrocytes and microglia to induce additional cytokine release involving IL-1 beta , IL-6, and IL-18, and also nitric oxide (NO) synthase that can stimulate production of free radical NO, leading to the forma- tion of peroxynitrite that denatures DNA and impairs cellular energy pathways [48, 49]. PubMed:27314526
It is noteworthy that IL-1 beta and IL-18 can activate various cell types, par- ticularly astrocytes and microglia to induce additional cytokine release involving IL-1 beta , IL-6, and IL-18, and also nitric oxide (NO) synthase that can stimulate production of free radical NO, leading to the forma- tion of peroxynitrite that denatures DNA and impairs cellular energy pathways [48, 49]. PubMed:27314526
Pro-inflammatory IL-18 increases AD-associated A beta deposition in human neuron-like cells in culture [55]. IL-18 also increases the expression of glycogen synthase kinase 3 beta (GSK-3 beta ) and cyclin-dependent kinase 5, both of which are involved in hyperphos- phorylation of the tau protein [56]. PubMed:27314526
Pro-inflammatory IL-18 increases AD-associated A beta deposition in human neuron-like cells in culture [55]. IL-18 also increases the expression of glycogen synthase kinase 3 beta (GSK-3 beta ) and cyclin-dependent kinase 5, both of which are involved in hyperphos- phorylation of the tau protein [56]. PubMed:27314526
Pro-inflammatory IL-18 increases AD-associated A beta deposition in human neuron-like cells in culture [55]. IL-18 also increases the expression of glycogen synthase kinase 3 beta (GSK-3 beta ) and cyclin-dependent kinase 5, both of which are involved in hyperphos- phorylation of the tau protein [56]. PubMed:27314526
TNF-α [27], IL-1β [28], IL-18 [29], CXCL10 [30] and TGF-β1 [31] are known to be elevated in the AD brain. PubMed:27288790
Cortical neurons stimulated with IL-18 also generated NF-κB activation [33]. PubMed:27288790
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