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NLRP3 inflammasome: a key player in neonatal brain injury

NLRP3 inflammasome: a key player in neonatal brain injury

Article information

Clin Exp Pediatr. 2025;68(7):475-485
Publication date (electronic) : 2025 April 1
doi : https://doi.org/10.3345/cep.2024.01935
1Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus, Izmir, Turkey
2Izmir International Biomedicine and Genome Institute, Dokuz Eylul University, Izmir, Turkey
3Department of Neonatology, Izmir Faculty of Medicine, University of Health Sciences, Izmir, Turkey
4Department of Neuroscience, Health Sciences Institute, Dokuz Eylul University, Izmir, Turkey
Corresponding author: Sermin Genc, MD. Izmir Biomedicine and Genome Center, Dokuz Eylul University Health Campus, Mithatpasa St. 58/5, 35340 Balcova, Izmir, Turkey Email: sermin.genc@deu.edu.tr, sermin.genc@ibg.edu.tr
Received 2024 December 13; Revised 2025 February 27; Accepted 2025 March 4.

Abstract

Among neonates, hypoxic-ischemic encephalopathy is the most significant cause of mortality and hypoxia-ischemia is among the leading causes of brain damage. The microglia are primary mediators of neuroinflammation. NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation is the first line of defense in the central nervous system. Numerous studies have shown that the NLRP3 inflammasome is activated and proinflammatory cytokines are upregulated upon hypoxia-ischemia–induced brain damage. However, aberrant activation of the NLRP3 inflammasome results in cell death and brain tissue damage. Given that neonates are particularly vulnerable to neuroinflammation, which may cause lifelong disabilities, it is important to target the pathways involved in its complex nature to improve their prognosis. The potential use of compounds or drugs that target inflammasome activation to relieve hypoxia-induced brain damage has become significant. This review describes the NLRP3 inflammasome in neonates to contribute to the development of therapeutic approaches.

Key message

Hypoxic-ischemic encephalopathy is the major cause of neonatal brain injury. NOD-like receptor family pyrin domain containing 3 inflammasome activation leads to neuroinflammation, which significantly affects newborn mortality. The establishment of preventive and therapeutic strategies against brain damage requires a thorough understanding of the mechanisms underlying neuroinflammation and inflammasome activation in the neonatal brain.

Graphical abstract. LPS, lipopolysaccharides; PAMP, pathogen-associated molecular pattern; DAMP, damageassociated molecular pattern; TLR4, Toll-like receptor 4; NLRP3, NOD-like receptor family pyrin domain containing 3; GSDMD, Caspase-1 also cleaves Gasdermin D.

Introduction

NOD-like receptor family pyrin domain containing 3 (NLRP3) protein, a cytosolic pattern recognition receptor [1], constitutes a multiprotein complex referred to as the NLRP3 inflammasome, which acts as the first line of defense in response to stimuli from invading pathogens or intracellular danger signals [2]. The NLRP3 inflammasome maintains homeostasis as the primary function of innate immunity [3]. The broad range of stimuli sensed by NLRP3 originates from microorganisms including bacteria, fungi, and viruses in the form of conserved structures collectively referred to as pathogen-associated molecular patterns (PAMPs). On the other hand, damage-associated molecular patterns (DAMPs) are found within or around cells under physiological conditions; however, once released upon cellular damage, disruption, or death, DAMPs act as molecular patterns [4], namely uric acid crystals, extracellular adenosine triphosphate (ATP), and beta-amyloid plaques [5]. The recognition of PAMPs and DAMPs by cellular receptors activates intracellular signaling pathways and triggers NLRP3 inflammasome assembly [6].

The NLRP3 inflammasome, the most extensively studied inflammasome, comprises 3 main components: NLRP3 receptor, a sensor protein; apoptosis-associated speck-like protein containing a Caspase recruitment domain (ASC); and effector protein pro-Caspase-1 [7]. The central protein of the inflammasome complex, NLRP3, has 3 domains: N-terminal pyrin domain (PYD), central NACHT domain as an oligomerization domain, and C-terminal leucine-rich repeat (LRR) domain [2]. Recognition of danger signals by the LRR domain results in the oligomerization of NLRP3 monomers through interactions with the NACHT domain [5]. The N-terminal PYD of NLRP3 is involved in ASC recruitment through PYD-PYD interactions, as PYD is one of the 2 protein-binding domains of ASC. The ASC speck is formed by multiple ASC filaments, which recruit pro-Caspase-1 through the second domain of ASC, C-terminal CARD [8].

NLRP3 inflammasome activation requires 2 separate signaling steps: priming and activation. NLRP3 and pro-interleukin (IL)-1β protein expressions are available at the basal level but low and insufficient, necessitating a priming signal (signal 1) to induce their transcription [5]. Priming stimuli can include ligands for receptors IL-1 receptor, Toll-like receptors (TLRs), and NOD-like receptors (NLRs) as well as cytokine receptors such as tumor necrosis factor (TNF) receptor, leading to the activation of the transcription factor nuclear factor kappa B (NF-κB) [3,9]. In the activation step (signal 2), the NLRP3 receptor is activated and the inflammasome complex subsequently formed through the recruitment of ASC and pro-Caspase-1. Intracellular ATP and K+ efflux, lysosomal destabilization, and mitochondrial reactive oxygen species (ROS) are among the molecular mechanisms underlying NLRP3 activation and complex formation [10]. Upon inflammasome complex formation, the effector protein Caspase-1 is activated; consequently, active Caspase-1 cleaves pro-IL-1β and pro-IL-18 cytokines and maturates each, leading to their secretion. Caspase-1 also cleaves Gasdermin D (GSDMD), which forms pores within the cellular membrane and eventually results in pyroptosis, a form of cell death [11].

NLRP3 inflammasome activation is involved in distinctive pathways in different cell types, namely, canonical, noncanonical, and alternative [12]. The subsequent activation of Caspase-1 and GSDMD follows the recruitment of ASC and pro-Caspase-1 [13]; thus, the priming and activation steps are generally referred to as the canonical pathways of NLRP3 inflammasome activation [14]. In contrast, human Caspase-4,5 or murine Caspase-11 can detect cytosolic lipopolysaccharides (LPS) originating from pathogens, including gram-negative bacteria [12]. In the noncanonical pathway, GSMDM is cleaved by the aforementioned caspases, resulting in pores within the cell membranes and leading to pyroptosis without necessitating inflammasome assembly [15]. In the noncanonical pathway, pyroptosis is directly induced, which leads to canonical cleavage and activation of the proinflammatory cytokines pro-IL-1β and pro-IL-18 [14]. Moreover, in the alternative activation pathway, NLRP3 and Caspase are involved in pro-IL-1β cleavage, maturation, and secretion; however, pyroptosis is not observed in this particular type of activation [16,17]. Alternative activation has been observed in human monocytes via Caspase-8 activation [18,19].

NLRP3 inflammasome activation has been implicated in various pathogenic diseases, particularly neuroinflammation, which is closely linked to neonatal brain injury. Several factors contribute to brain injuries in newborns. Hypoxic-ischemic encephalopathy (HIE) is a leading cause of brain injury, severe neurologic disability, and death in infants worldwide [20,21]. Neuroinflammation following hypoxia-ischemia (HI) causes neuronal injury and brain cell death in HIE [22]. HIE is characterized by immune response activation and ROS and nitrogen species generation, mitochondrial damage, and interrupted vascular flow. Microglial cells play a primary role in neuroinflammation during HIE [23,24]. Aberrant microglial activation causes widespread neuroinflammation, ultimately leading to cellular death [25]. Infections such as chorioamnionitis and neonatal sepsis can also initiate inflammatory responses that harm the brain. Prematurity is another significant risk factor since preterm infants are especially susceptible to hyperoxia and other forms of brain injury owing to their immature neurological development. One critical aspect of this injury is periventricular leukomalacia (PVL), a condition characterized by death of the white matter near the ventricles that is frequently associated with preterm birth. Neuroinflammation plays a crucial role in PVL, as the activation of glial cells and release of proinflammatory cytokines can exacerbate neuronal damage and disrupt normal brain development [26,27].

Hyperbilirubinemia can also increase a newborn's risk of brain injury. The fat-soluble nature of bilirubin enables it to pass through the blood–brain barrier and aggregate within the brain cells [28]. Understanding the underlying mechanisms is essential to the development of effective prevention and early intervention strategies [29]. Collectively, these neonatal diseases disrupt the developing brain and contribute to neuroinflammation. Although in vitro modeling of neonatal brain injuries is challenging, a few in vitro and in vivo disease models and clinical studies have investigated brain injury and NLRP3 inflammasome activation in neonates. This review investigates the role of the NLRP3 inflammasome in conditions that lead to neonatal brain injury (Fig. 1) and discusses possible therapeutic approaches.

Fig. 1.

Summary of neonatal brain damage-induced NLRP3 inflammasome activation and related pathways. The NLRP3 inflammasome is activated upon neonatal brain damage and plays an important role in neuroinflammation. Once PAMPs activate TLR4 signaling and DAMPs are sensed by NLRP3 within the cell, the NLRP3 inflammasome complex is formed, and the proinflammatory cytokines IL-1β and IL-18 are cleaved by active Caspase-1 and secreted. Several pathways are associated with NLRP3 inflammasome activation in neonatal brain damage, namely PI3K/Akt, JAK2/STAT3, mTOR, the Smad6 axis, and miRNAs. DAMPs, damage-associated molecular patterns; IL, interleukin; mTOR, mammalian target of rapamycin; NLRP3, NOD-like receptor family pyrin domain containing 3; PAMPs, pathogen-associated molecular patterns; PI3K, phosphoinositide 3-kinase; TLR4, Toll-like receptor 4; LPS, lipopolysaccharides; ATP, adenosine triphosphate; P2X7R, P2X7 receptor; HMGB1, high mobility group box 1; TRPV1, transient receptor potential vanilloid 1; TXNIP, thioredoxin-interacting protein; JAK2, Janus kinase 2; STAT3, signal transducer and activator of transcription 3; JMJD3, Jumonji domain-containing protein 3; GSDMD, Gasdermin D; NF- κB, nuclear factor κB. Graphic created using Biorender.

Evidence of NLRP3 inflammasome activation in in vitro model of neonatal brain injury

1. Microglia

Microglia, the resident immune cells that act as the first line of defense in the central nervous system (CNS), have numerous functions including immune surveillance, synaptic pruning, phagocytosis, and CNS development [30]. Given that in vitro modeling of neonatal brain injury is complicated, only a limited number of studies have been conducted (Table 1). For the in vitro HI model, an oxygen/glucose deprivation (OGD) method was used under hypoxic conditions. Previous studies demonstrated that the proinflammatory parameters TNF-α, IL-1β, inducible nitric oxide synthase, and NF-κB were upregulated upon OGD in primary microglia of 3-day-old rats and a BV2 microglia cell line [31-33]. In a recent study of microglial inflammation in neonatal HIE, Caspase-1 and GSDMD expression levels were elevated in BV2 microglia-like cells upon OGD. The authors employed recombinant high mobility group box 1 (HMGB1) to show that Caspase-1 and GSDMD levels were further increased, whereas use of the HMGB1 inhibitor glycyrrhizin significantly alleviated Caspase-1 and GSDMD expression levels. Cell viability significantly decreased in HT22 hippocampal neuron-like cells incubated with conditioned medium from BV2 microglia subjected to OGD, suggesting that its effect on neurons occurs through microglial inflammasome activation [24].

Mechanisms of action of in vitro models of hypoxia-induced NLRP3 inflammasome activation

Bilirubin, an inducer of neuroinflammation, causes pyroptosis [34]. Upon free bilirubin treatment, HMGB1, TNF-α, IL-1β, IL-6, IL-10, and Arg1 levels were upregulated in microglia isolated from neonatal mice [35]. Furthermore, in primary microglia isolated from the cerebral cortex of neonatal rats, treatment raised NLRP3 and ASC protein levels, ASC speck formation, and IL-1β cytokine mRNA and protein levels. Bilirubin-induced increases in NLRP3 and ASC levels are mitigated by rapamycin, a mammalian target of rapamycin inhibitor [36]. We recently demonstrated that bilirubin-induced neurological dysfunction in newborns is mediated by NLRP3 inflammasome activation. We also demonstrated that active Caspase-1 and IL-1β release, as well as final cell death, are significantly connected with the upregulation of NLRP3 expression in N9 microglial cells exposed to bilirubin. To ascertain whether NLRP3 was necessary for bilirubin-induced inflammation, we performed functional in vitro studies using NLRP3 small interfering RNA. Our results suggested that the NLRP3 inflammasome is most likely responsible for bilirubin-induced inflammasome activation and cellular death [37].

LPS are often used to introduce neuroinflammation [38]. Other studies investigating NLRP3 inflammasome activation in the microglia of neonates demonstrated that LPS treatment in primary microglia derived from neonatal rats led to upregulation of the inflammasome markers NLRP3, ASC, and Caspase-1 and increased expression levels of the proinflammatory cytokines TNF-α, IL-1b, IL-6, and IL-8 [20,39]. We also showed that LPS-induced NLRP3 and ASC levels and -cleaved Caspase-1 protein levels were reduced by miR-374a-5p, which targets Smad6 [20]. Additionally, osteopontin, a secretory extracellular matrix glycoprotein, reduces elevated levels of inflammasome parameters and cytokines [39].

Studies have shown that other factors induce inflammasome activation. The TLR4 agonist serum amyloid A protein (SAA) has an effect similar to that of LPS in NLRP3 inflammasome activation. In this study, LPS and SAA treatment increased NLRP3 levels and IL-1β cytokine secretion. Use of the P2X7R antagonist alleviated the IL-1β levels in primary rat microglia [40]. In addition, limited studies investigated NLRP3 inflammasome activation in neonates against bacterial infections. Neonatal meningitis-associated Escherichia coli (NMEC) causes sepsis and meningitis in newborns. In a recent study, the levels of proinflammatory cytokines IL-1b and IL-1a increased upon NMEC infection. When microglia were treated with an inhibitor of NLRP3-dependent Caspase-1 activation (MCC950), IL-1b and IL-1a secretions were attenuated, suggesting that cytokine secretion in response to infection was dependent on the NLRP3 inflammasome. The evidence indicates that neonatal neuroinflammation depends on microglial NLRP3 inflammasome activation via the TLR4/Myd88 axis [41]. Together, these findings suggest that NLRP3 inflammasome activation occurs through numerous factors and that subsequent proinflammatory cytokine secretion is involved in microglia-induced neuroinflammation in neonates.

2. Astrocytes

Astrocytes are glial cells in the CNS involved in numerous processes, including neurodegeneration and hypoxiainduced brain death (HIBD). Studies have shown that NLRP3, ASC, and Caspase-1 inflammasome parameters as well as the proinflammatory cytokines TNF-α, IL-1β, IL-10, and IL-6 are increased in primary cultured hippocampal astrocytes upon OGD [42]. In another study of primary rat astrocytes, when the cells were treated with OGD and subjected to hypoxia, NLRP3 and cleaved Caspase-1 were significantly upregulated, whereas treatment with the ZJU37 inhibitor receptor-interacting protein kinase-1/-3 attenuated this increase. NLRP3, ASC, Caspase-1, GSDMD, IL-1β, and IL-18 levels were elevated in primary hippocampal astrocytes after OGD. Dexmedetomidine relieved the expressions of inflammasome parameters and proinflammatory cytokines [43]. NLRP3 inflammasome activation was also observed in cultured rat astrocytes treated with unconjugated bilirubin. NLRP3 protein level, Caspase-1 activity, and IL-1β and IL-18 cytokine levels and pyroptosis were increased upon bilirubin treatment. These increased levels were attenuated by VX-765 treatment [44]. Altogether, these results suggest that hypoxia activates the NLRP3 inflammasome in the microglia and astrocytes of the CNS. Evidence also indicates that hypoxic microglia are involved in pyroptotic cell death and proinflammatory mediator production. Targeting microglial NLRP3 inflammasome activation would be a promising way to attenuate cell death and neuronal injury as well as improve HIBD pathophysiology. Given the current lack of effective treatment for HIBD, it is important to establish a target to relieve damage progression.

3. Neurons

Furthermore, NLRP3 inflammasome activation and microglial inflammation during neonatal brain damage have been investigated in neuronal cells. Neurons are the cells of the brain that are involved in information exchange within the CNS and have unique roles in the CNS [45]. Following HIBD, neuronal cell death occurs in the neonatal brain [46].

A neonatal HIBD model was established using CoCl2-induced PC12 pheochromocytoma cells, which are widely used in HIBD studies. The authors provided evidence that CoCl2 decreases neuronal viability following HIBD. Moreover, expression levels of TNF-α, IL-1β, IL-18, and IL-6 proinflammatory cytokines as well as NF-κB, Iκb, NLRP3, ASC, and Caspase-1 were significantly upregulated [22,46]. In another study, the OGD-induced increases in NLRP3, ASC, and Caspase-1 were suppressed by HIBD-associated peptide treatment in PC12 rat cells [47]. Treatment with diallyl disulfide reverses this increase in NLRP3 inflammasome parameters and cellular death [46]. Moreover, NLRP3, Caspase-1, and IL-1β levels were significantly increased in OGD-treated primary neurons isolated from D18 rat fetuses [48]. Together, these findings suggest that the microglial NLRP3 inflammasome plays a significant pathological role in HIBD and that its activation could rescue HIBD-induced neuronal damage.

In vivo NLRP3 inflammasome activation in neonatal brain injury

1. Hypoxia

In vitro NLRP3 inflammasome activation upon hypoxia initiated further investigations of NLRP3 inflammasome activation in vivo to elucidate its physiological validity (Table 2). In an in vivo study, NLRP3 was upregulated upon neonatal HI in mice. Within 24 hours of HI, NLRP3 expression was significantly increased in the brain [49]. In this study, we investigated whether NLRP3 or ASC deficiency protected against neonatal HI brain injury. RNA sequencing data revealed impaired the NLRP3-/- murine hippocampal transcriptional response to inflammation. TNF-α levels were also decreased in NLRP3-/- and ASC-/- versus wild-type mice, whereas plasma levels of IL-1 and IL-18 were unaffected. The authors concluded that ASC deficiency is neuroprotective but that NLRP3 deficiency exacerbates brain damage later in the course of neonatal HIBD [50]. Thus, here we confirmed the importance of NLRP3 inflammasome activation in neonatal HIBD.

Mechanisms of action of in vivo models of hypoxia-induced NLRP3 inflammasome activation

A number of studies have shown activation of the NLRP3 inflammasome and increased levels of the proinflammatory cytokines IL-1β, IL-18, and IL-10 as well as increased mRNA and protein expressions of NLRP3 and Caspase-1 in rat models of neonatal HIBD [48,51-55]. These findings reveal that NLRP3 inflammasome activation further activates pathways that contribute to neuroinflammation in HIBD. The identification of the underlying mechanisms and pathways could contribute to the development of potential treatments by targeting these pathways.

In animal models of neonatal HIBD, brain injury is reduced by several medications that block NLRP3 activation. These studies also investigated downstream processes. For example, the administration of Gingko biloba prior to ischemia induction prevents activation of the NLRP3 inflammasome and reduces brain damage [56]. Moreover, in a neonatal HIBD model in rats, inositol-requiring transmembrane kinase/endoribonuclease 1α suppression reduced TXNIP/NLRP3 inflammasome activation through miR-17-5p [57]. Another study found that the administration of MCC950, an NLRP3 inhibitor, dramatically reduced pyroptosis in a rat model of neonatal HIBD [21]. The increased expression levels of NLRP3 and downstream inflammatory factors including IL-1β and IL-18 were reduced by melatonin therapy via mitochondrial autophagy and TLR4/NF-κB pathway activity reduction [58].

Furthermore, in a rat model of HIBD, an N-acetylserotonin derivative exerted neuroprotective effects by activating the PI3K/Akt/Nrf2 pathway and inhibiting the NLRP3 inflammasome [59]. Neferine, an alkaloid extracted from lotus seed embryo, was also used as a rescue therapy in a rat model of HI. Authors showed that, compared to the control group, newborn HI model rats had significantly higher levels of Caspase-1, ASC, GSDMD, TNF-α, IL-β, IL-18, and IL-6. Treatment with neferine considerably decreased these variables [22]. In another study, caffeine treatment alleviated NLRP3 inflammasome activation in neonatal rats [54]. IL-1β, IL-18 NLRP3, ASC, Caspase-1, and GSDMD levels were elevated upon HIBD in hippocampal astrocytes of neonatal rats. Dexmedetomidine treatment mitigates these elevated levels [43,60]. In another study, an HIBD model was established in wild-type and Nrf2-/- mice. Hydrogen treatment alleviated cellular injury and the inflammatory response following HI via the Nrf2-mediated NLRP3 and NF-κB pathways. The absence of Nrf2 abolishes the suppressive effect of hydrogen on NLRP3 pathway expression [61]. Interestingly, another study showed that maternal treadmill exercise attenuated alterations in Caspase-1 and NLRP3 gene expression and provided better neurological outcomes in a rat model of neonatal HI [53]. These results suggest that addressing NLRP3 inflammasome activation is important for attenuating HIBD, although the long-term effects of these agents at the cellular and behavioral levels were not investigated in the aforementioned studies.

2. Hyperoxia and preterm brain injury

In addition to hypoxia-induced brain injury, hyperoxic brain damage occurs via NLRP3 inflammasome activation in newborns. Our group demonstrated for the first time that exposure to O2 in the early periods of life elevated NLRP3 expression in a mouse model of preterm brain injury. The neonatal murine brain displayed a global increase in immunopositive cells for NLRP3 and IL-1β after 7 days of hyperoxic exposure. Hyperoxia-treated mice demonstrated a significant increase in the number of Caspase-1 positive cells in the prefrontal and parietal areas [62].

3. Infections

Sepsis and meningitis are intertwined conditions in neonates that occur in response to bacterial infections. One study found that postnatal day 10 rats with sepsis had considerably higher levels of NLRP3, Caspase-1, and the proinflammatory cytokines TNFα, IL-1β, and IL-6. They also discovered that sepsis elevated the levels of phosphorylated p38-MAPK and extracellular signal-regulated kinase (ERK) in the cortex. Treatment with recombinant club cell protein 16 treatment inhibited the increased levels of phospo-p38-MAPK and phospho-ERK as well as the expression levels of NLRP3, Caspase-1, and proinflammatory cytokines [63]. In another study, IL-1b and IL-1a were secreted from microglia upon induction with neonatal meningitis-associated Escherichia coli. To further elucidate whether cytokine secretion is dependent on NLRP3 inflammasome activation, we used NLRP3 ad Caspase-1 knockout mice and observed diminished cytokine secretion [41].

4. Neonatal jaundice

Unconjugated bilirubin is another inducer of the NLRP3 inflammasome in the newborn brain. Bilirubin-induced encephalopathy impairs multiple brain regions, including the hippocampus and the basal ganglia. NLRP3 and ASC protein levels increased in the hippocampal tissue obtained from rats after a bilirubin injection, while rapamycin treatment reduced bilirubin-induced neuroinflammation [36]. Our group revealed, for the first time, that bilirubin activates microglial NLRP3 inflammasomes in vitro and in vivo in newborn brains [37]. Bilirubin treatment noticeably increased neuronal loss in wild-type versus Nlrp3-/- and Caspase-1-/- mice. Taken together, our findings suggest that the NLRP3 inflammasome is essential for microglial activation and bilirubin-induced neuronal damage [37].

Clinical studies in NLRP3 inflammasome activation

Numerous in vitro and in vivo studies have investigated NLRP3 inflammasome activation and its potential drug targets for clinical studies. A few studies have examined the NLRP3 inflammasome in neonates. For example, NLRP3 inflammasome activation was examined in serum samples from patients with neonatal encephalopathy (NE) in the clinical setting. Serum samples were collected on a serial basis during the early weeks after birth and at school age from 40 babies with NE and 19 healthy babies. No difference was observed in NLRP3 expression in the peripheral blood of neonates with NE versus healthy controls at baseline. However, when the serum samples were stimulated with LPS in neonates with NE, NLRP3 expression was upregulated on day 3 versus baseline. ASC expression was comparable between controls and patients with NE and remained unchanged after LPS stimulation compared to nonstimulation in newborns. Compared with LPS-stimulated controls, school-aged children with NE had higher NLRP3 levels after LPS stimulation [64].

NLRP3 inflammasome activation is also crucial in the pathogenesis of other neonatal conditions, including Zika virus infection, that leads to significant CNS damage, particularly among those with microcephaly [65]. An association between NLRP3 and neuroinflammation was also observed in cryopyrin-associated periodic syndromes (CAPS), a group of rare autoinflammatory diseases caused by NLRP3 gene mutations. Neonatal-onset multisystem inflammatory disease (NOMID), a severe form of CAPS, is characterized by systemic inflammation, neurological impairment, skin rashes, and arthritic manifestations. In these patients, NLRP3 mutations lead to dysregulated inflammatory responses that severely affect multiple organ systems including the CNS [66]. Anakinra, an IL-1 receptor antagonist, demonstrated promising long-term efficacy at controlling systemic inflammation and ameliorating neurological symptoms in patients with NOMID. However, its effectiveness depends on treatment timing, i.e., early intervention prevents irreversible damage, while delays in diagnosis and treatment may lead to persistent symptoms, such as CNS inflammation, hearing loss, and secondary amyloidosis [67]. In summary, these findings underscore the importance of NLRP3 inflammasome activation in the progression of neonatal diseases and highlight the therapeutic potential of targeting this pathway in inflammatory conditions.

Conclusion

Understanding the mechanisms driving newborn brain injury is critical to the development of preventive and therapeutic measures such as the reagents mentioned in this article (Table 3). We can better identify at-risk populations and design tailored therapies by understanding the complex processes involved in neonatal brain injury, such as neuroinflammation and the functions of specific molecular players such as the NLRP3 inflammasome. This understanding not only improves our capacity to minimize acute damage, but it may improve the long-term results for affected infants. As research on the complexity of neonatal brain injury progresses, collaboration across disciplines will be critical to converting the results into effective therapeutic practices, eventually protecting the health and development of vulnerable babies.

Potential preventive or therapeutic reagents used in in vitro, in vivo and clinical studies mentioned in this article

Notes

Conflicts of interest

No potential conflict of interest relevant to this article was reported.

Funding

This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Author Contribution

Conceptualization: SG; Writing-original draft: CK, IE, DE; Writing-review & editing: CK, IE, DE, SG

References

1. Elliott EI, Sutterwala FS. Initiation and perpetuation of NLRP3 inflammasome activation and assembly. Immunol Rev 2015;265:35–52.
2. Kelley N, Jeltema D, Duan Y, He Y. The NLRP3 inflammasome: an overview of mechanisms of activation and regulation. Int J Mol Sci 2019;20:3328.
3. Sutterwala FS, Haasken S, Cassel SL. Mechanism of NLRP3 inflammasome activation. Ann N Y Acad Sci 2014;1319:82–95.
4. Pittman K, Kubes P. Damage-associated molecular patterns control neutrophil recruitment. J Innate Immun 2013;5:315–23.
5. Zahid A, Li B, Kombe AJK, Jin T, Tao J. Pharmacological Inhibitors of the NLRP3 Inflammasome. Front Immunol 2019;10:2538.
6. Yang Y, Wang H, Kouadir M, Song H, Shi F. Recent advances in the mechanisms of NLRP3 inflammasome activation and its inhibitors. Cell Death Dis 2019;10:128.
7. Moretti J, Blander JM. Increasing complexity of NLRP3 inflammasome regulation. J Leukoc Biol 2021;109:561–71.
8. Freeman TL, Swartz TH. Targeting the NLRP3 Inflammasome in Severe COVID-19. Front Immunol 2020;11:1518.
9. Omer M, Melo AM, Kelly L, Mac Dermott EJ, Leahy TR, Killeen O, et al. Emerging role of the NLRP3 inflammasome and interleukin-1beta in neonates. Neonatology 2020;117:545–54.
10. Biasizzo M, Kopitar-Jerala N. Interplay between NLRP3 inflammasome and autophagy. Front Immunol 2020;11:591803.
11. Nizami S, Arunasalam K, Green J, Cook J, Lawrence CB, Zarganes-Tzitzikas T, et al. Inhibition of the NLRP3 inflammasome by HSP90 inhibitors. Immunology 2021;162:84–91.
12. Li Z, Chen X, Tao J, Shi A, Zhang J, Yu P. Exosomes regulate NLRP3 inflammasome in diseases. Front Cell Dev Biol 2021;9:802509.
13. Al Mamun A, Mimi AA, Zaeem M, Wu Y, Monalisa I, Akter A, et al. Role of pyroptosis in diabetic retinopathy and its therapeutic implications. Eur J Pharmacol 2021;904:174166.
14. Xu Z, Chen ZM, Wu X, Zhang L, Cao Y, Zhou P. Distinct molecular mechanisms underlying potassium efflux for NLRP3 inflammasome activation. Front Immunol 2020;11:609441.
15. Gou X, Xu D, Li F, Hou K, Fang W, Li Y. Pyroptosis in strokenew insights into disease mechanisms and therapeutic strategies. J Physiol Biochem 2021;77:511–29.
16. He Y, Hara H, Nunez G. Mechanism and regulation of NLRP3 inflammasome activation. Trends Biochem Sci 2016;41:1012–21.
17. Hafner-Bratkovic I, Pelegrin P. Ion homeostasis and ion channels in NLRP3 inflammasome activation and regulation. Curr Opin Immunol 2018;52:8–17.
18. Gaidt MM, Hornung V. Alternative inflammasome activation enables IL-1beta release from living cells. Curr Opin Immunol 2017;44:7–13.
19. Mezzasoma L, Talesa VN, Romani R, Bellezza I. ANP and BNP exert anti-inflammatory action via NPR-1/cGMP axis by interfering with canonical, non-canonical, and alternative routes of inflammasome activation in human THP1 cells. Int J Mol Sci 2020;22:24.
20. Chen Z, Hu Y, Lu R, Ge M, Zhang L. MicroRNA-374a-5p inhibits neuroinflammation in neonatal hypoxic-ischemic encephalopathy via regulating NLRP3 inflammasome targeted Smad6. Life Sci 2020;252:117664.
21. Lv Y, Sun B, Lu XX, Liu YL, Li M, Xu LX, et al. The role of microglia mediated pyroptosis in neonatal hypoxic-ischemic brain damage. Biochem Biophys Res Commun 2020;521:933–8.
22. Zhu JJ, Yu BY, Huang XK, He MZ, Chen BW, Chen TT, et al. Neferine protects against hypoxic-ischemic brain damage in neonatal rats by suppressing NLRP3-mediated inflammasome activation. Oxid Med Cell Longev 2021;2021:6654954.
23. Hagberg H, Mallard C, Ferriero DM, Vannucci SJ, Levison SW, Vexler ZS, et al. The role of inflammation in perinatal brain injury. Nat Rev Neurol 2015;11:192–208.
24. Zhu K, Zhu X, Yu J, Chen L, Liu S, Yan M, et al. Effects of HMGB1/RAGE/cathespin B inhibitors on alleviating hippocampal injury by regulating microglial pyroptosis and caspase activation in neonatal hypoxic-ischemic brain damage. J Neurochem 2023;167:410–26.
25. Li B, Concepcion K, Meng X, Zhang L. Brain-immune interactions in perinatal hypoxic-ischemic brain injury. Prog Neurobiol 2017;159:50–68.
26. Shao R, Sun D, Hu Y, Cui D. White matter injury in the neonatal hypoxic-ischemic brain and potential therapies targeting microglia. J Neurosci Res 2021;99:991–1008.
27. Khurana R, Shyamsundar K, Taank P, Singh A. Periventricular leukomalacia: an ophthalmic perspective. Med J Armed Forces India 2021;77:147–53.
28. Huang J, Zhao Q, Li J, Meng J, Li S, Yan W, et al. Correlation between neonatal hyperbilirubinemia and vitamin D levels: a meta-analysis. PLoS One 2021;16e0251584.
29. Novak CM, Ozen M, Burd I. Perinatal brain injury: mechanisms, prevention, and outcomes. Clin Perinatol 2018;45:357–75.
30. Lu W, Wen J. Neuroinflammation and post-stroke depression: focus on the microglia and astrocytes. Aging Dis 2024;16:394–407.
31. Suk K. Minocycline suppresses hypoxic activation of rodent microglia in culture. Neurosci Lett 2004;366:167–71.
32. Yao L, Kan EM, Lu J, Hao A, Dheen ST, Kaur C, et al. Toll-like receptor 4 mediates microglial activation and production of inflammatory mediators in neonatal rat brain following hypoxia: role of TLR4 in hypoxic microglia. J Neuroinflammation 2013;10:23.
33. Zhou T, Huang YX, Song JW, Ma QM. Thymosin beta4 inhibits microglia activation through microRNA 146a in neonatal rats following hypoxia injury. Neuroreport 2015;26:1032–8.
34. Silva SL, Vaz AR, Barateiro A, Falcao AS, Fernandes A, Brito MA, et al. Features of bilirubin-induced reactive microglia: from phagocytosis to inflammation. Neurobiol Dis 2010;40:663–75.
35. Vaz AR, Falcao AS, Scarpa E, Semproni C, Brites D. Microglia susceptibility to free bilirubin is age-dependent. Front Pharmacol 2020;11:1012.
36. Li L, Li S, Pan Z, Zhang Y, Hua Z. Bilirubin impacts microglial autophagy via the Akt-mTOR signaling pathway. J Neurochem 2023;167:582–99.
37. Ercan I, Cilaker Micili S, Soy S, Engur D, Tufekci KU, Kumral A, et al. Bilirubin induces microglial NLRP3 inflammasome activation in vitro and in vivo. Mol Cell Neurosci 2023;125:103850.
38. Millar LJ, Shi L, Hoerder-Suabedissen A, Molnar Z. Neonatal hypoxia ischaemia: mechanisms, models, and therapeutic challenges. Front Cell Neurosci 2017;11:78.
39. Zhang X, Shu Q, Liu Z, Gao C, Wang Z, Xing Z, et al. Recombinant osteopontin provides protection for cerebral infarction by inhibiting the NLRP3 inflammasome in microglia. Brain Res 2021;1751:147170.
40. Facci L, Barbierato M, Zusso M, Skaper SD, Giusti P. Serum amyloid A primes microglia for ATP-dependent interleukin-1beta release. J Neuroinflammation 2018;15:164.
41. Chambers CA, Lacey CA, Brown DC, Skyberg JA. Nitric oxide inhibits interleukin-1-mediated protection against Escherichia coli K1-induced sepsis and meningitis in a neonatal murine model. Immunol Cell Biol 2021;99:596–610.
42. Yang XL, Wang X, Shao L, Jiang GT, Min JW, Mei XY, et al. TRPV1 mediates astrocyte activation and interleukin-1beta release induced by hypoxic ischemia (HI). J Neuroinflammation 2019;16:114.
43. Zhong Y, Wang S, Yin Y, Yu J, Liu Y, Gao H. Dexmedetomidine suppresses hippocampal astrocyte pyroptosis in cerebral hypoxic-ischemic neonatal rats by upregulating microRNA-148a-3p to inactivate the STAT/JMJD3 axis. Int Immunopharmacol 2023;121:110440.
44. Feng J, Li M, Wei Q, Li S, Song S, Hua Z. Unconjugated bilirubin induces pyroptosis in cultured rat cortical astrocytes. J Neuroinflammation 2018;15:23.
45. Lovinger DM. Communication networks in the brain: neurons, receptors, neurotransmitters, and alcohol. Alcohol Res Health 2008;31:196–214.
46. Zheng Y, Zhu T, Chen B, Fang Y, Wu Y, Feng X, et al. Diallyl disulfide attenuates pyroptosis via NLRP3/Caspase-1/IL-1beta signaling pathway to exert a protective effect on hypoxic-ischemic brain damage in neonatal rats. Int Immunopharmacol 2023;124(Pt B):111030.
47. Hou X, Yuan Z, Wang X, Cheng R, Zhou X, Qiu J. Peptidome analysis of cerebrospinal fluid in neonates with hypoxicischemic brain damage. Mol Brain 2020;13:133.
48. Chen Y, Li X, Xiong Q, Du Y, Luo M, Yi L, et al. Inhibiting NLRP3 inflammasome signaling pathway promotes neurological recovery following hypoxic-ischemic brain damage by increasing p97-mediated surface GluA1-containing AMPA receptors. J Transl Med 2023;21:567.
49. Ystgaard MB, Sejersted Y, Løberg EM, Lien E, Yndestad A, Saugstad OD. Early upregulation of NLRP3 in the brain of neonatal mice exposed to hypoxia-ischemia: no early neuroprotective effects of NLRP3 deficiency. Neonatology 2015;108:211–9.
50. Ystgaard MB, Scheffler K, Suganthan R, Bjørås M, Ranheim T, Sagen EL, et al. Neuromodulatory effect of NLRP3 and ASC in neonatal hypoxic ischemic encephalopathy. Neonatology 2019;115:355–62.
51. Bernis ME, Zweyer M, Maes E, Schleehuber Y, Sabir H. Neutrophil extracellular traps release following hypoxicischemic brain injury in newborn rats treated with therapeutic hypothermia. Int J Mol Sci 2023;24:3598.
52. Bernis ME, Schleehuber Y, Zweyer M, Maes E, Felderhoff- Muser U, Picard D, et al. Temporal characterization of microglia-associated pro- and anti-inflammatory genes in a neonatal inflammation-sensitized hypoxic-ischemic brain injury model. Oxid Med Cell Longev 2022;2022:2479626.
53. Gorgij E, Fanaei H, Yaghmaei P, Shahraki MR, Mirahmadi H. Maternal treadmill exercise ameliorates impairment of neurological outcome, caspase-1 and NLRP3 gene expression alteration in neonatal hypoxia-ischemia rats. Iran J Basic Med Sci 2023;26:228–34.
54. Yang L, Yu X, Zhang Y, Liu N, Xue X, Fu J. Caffeine treatment started before injury reduces hypoxic-ischemic white-matter damage in neonatal rats by regulating phenotypic microglia polarization. Pediatr Res 2022;92:1543–54.
55. Yang L, Zhang Y, Yu X, Li D, Liu N, Xue X, et al. Periventricular microglia polarization and morphological changes accompany NLRP3 inflammasome-mediated neuroinflammation after hypoxic-ischemic white matter damage in premature rats. J Immunol Res 2023;2023:5149306.
56. Chen A, Xu Y, Yuan J. Ginkgolide B ameliorates NLRP3 inflammasome activation after hypoxic-ischemic brain injury in the neonatal male rat. Int J Dev Neurosci 2018;69:106–11.
57. Chen D, Dixon BJ, Doycheva DM, Li B, Zhang Y, Hu Q, et al. IRE1α inhibition decreased TXNIP/NLRP3 inflammasome activation through miR-17-5p after neonatal hypoxic-ischemic brain injury in rats. J Neuroinflammation 2018;15:32.
58. Qin M, Liu Y, Sun M, Li X, Xu J, Zhang L, et al. Protective effects of melatonin on the white matter damage of neonatal rats by regulating NLRP3 inflammasome activity. Neuroreport 2021;32:739–47.
59. Luo X, Zeng H, Fang C, Zhang BH. N-acetylserotonin derivative exerts a neuroprotective effect by Inhibiting the NLRP3 inflammasome and activating the PI3K/Akt/Nrf2 pathway in the model of hypoxic-ischemic brain damage. Neurochem Res 2021;46:337–48.
60. Serdar M, Kempe K, Herrmann R, Picard D, Remke M, Herz J, et al. Involvement of CXCL1/CXCR2 during microglia activation following inflammation-sensitized hypoxicischemic brain injury in neonatal rats. Front Neurol 2020;11:540878.
61. Hu Y, Wang P, Han K. Hydrogen attenuated inflammation response and oxidative in hypoxic ischemic encephalopathy via Nrf2 mediated the inhibition of NLRP3 and NF-κB. Neuroscience 2022;485:23–36.
62. Micili SC, Engür D, Genc S, Ercan I, Soy S, Baysal B, et al. Oxygen exposure in early life activates NLRP3 inflammasome in mouse brain. Neurosci Lett 2020;738:135389.
63. Zhou R, Yang X, Li X, Qu Y, Huang Q, Sun X, et al. Recombinant CC16 inhibits NLRP3/caspase-1-induced pyroptosis through p38 MAPK and ERK signaling pathways in the brain of a neonatal rat model with sepsis. J Neuroinflammation 2019;16:239.
64. Kelly LA, O'Dea MI, Zareen Z, Melo AM, McKenna E, Strickland T, et al. Altered inflammasome activation in neonatal encephalopathy persists in childhood. Clin Exp Immunol 2021;205:89–97.
65. de Sousa JR, Azevedo R, Martins Filho AJ, de Araujo MT, Cruz E, Vasconcelos BC, et al. In situ inflammasome activation results in severe damage to the central nervous system in fatal Zika virus microcephaly cases. Cytokine 2018;111:255–64.
66. Neven B, Callebaut I, Prieur AM, Feldmann J, Bodemer C, Lepore L, et al. Molecular basis of the spectral expression of CIAS1 mutations associated with phagocytic cell-mediated autoinflammatory disorders CINCA/NOMID, MWS, and FCU. Blood 2004;103:2809–15.
67. Neven B, Marvillet I, Terrada C, Ferster A, Boddaert N, Couloignier V, et al. Long-term efficacy of the interleukin-1 receptor antagonist anakinra in ten patients with neonatal-onset multisystem inflammatory disease/chronic infantile neurologic, cutaneous, articular syndrome. Arthritis Rheum 2010;62:258–67.
68. Zhang C, Guan Q, Shi H, Cao L, Liu J, Gao Z, et al. A novel RIP1/RIP3 dual inhibitor promoted OPC survival and myelination in a rat neonatal white matter injury model with hOPC graft. Stem Cell Res Ther 2021;12:462.

Article information Continued

Fig. 1.

Summary of neonatal brain damage-induced NLRP3 inflammasome activation and related pathways. The NLRP3 inflammasome is activated upon neonatal brain damage and plays an important role in neuroinflammation. Once PAMPs activate TLR4 signaling and DAMPs are sensed by NLRP3 within the cell, the NLRP3 inflammasome complex is formed, and the proinflammatory cytokines IL-1β and IL-18 are cleaved by active Caspase-1 and secreted. Several pathways are associated with NLRP3 inflammasome activation in neonatal brain damage, namely PI3K/Akt, JAK2/STAT3, mTOR, the Smad6 axis, and miRNAs. DAMPs, damage-associated molecular patterns; IL, interleukin; mTOR, mammalian target of rapamycin; NLRP3, NOD-like receptor family pyrin domain containing 3; PAMPs, pathogen-associated molecular patterns; PI3K, phosphoinositide 3-kinase; TLR4, Toll-like receptor 4; LPS, lipopolysaccharides; ATP, adenosine triphosphate; P2X7R, P2X7 receptor; HMGB1, high mobility group box 1; TRPV1, transient receptor potential vanilloid 1; TXNIP, thioredoxin-interacting protein; JAK2, Janus kinase 2; STAT3, signal transducer and activator of transcription 3; JMJD3, Jumonji domain-containing protein 3; GSDMD, Gasdermin D; NF- κB, nuclear factor κB. Graphic created using Biorender.

Table 1.

Mechanisms of action of in vitro models of hypoxia-induced NLRP3 inflammasome activation

Cell line Model/inducer Outcome Mechanism References
BV2 microglia cell line OGD Caspase-1 ↑, GSDMD ↑ HMGB1/RAGE/Catepsin [24]
Primary microglia from 1- to 2-day-old CD1 mice Free bilirubin for 24 hr HMGB1↑, TNF-α↑, IL-1β↑, IL-6↑, IL-10↑, Arg1↑ - [35]
Primary microglia from cerebral cortex of neonatal rats Unconjugated bilirubin for 24 hr NLRP3 ↑, ASC ↑, IL-1β ↑ Akt–mTOR [36]
N9 microglia cell line Bilirubin and LPS for 6 hr NLRP3 ↑, Caspase-1 ↑, IL-1β ↑ - [37]
Primary microglia postnatal day-1 rat LPS for 24 hr NLRP3 ↑, ASC↑, Caspase-1↑, TNF-α↑, IL-1β↑, IL-6↑ miR-374a-5p – Smad6 [20]
Primary microglia culture from 1/3-day-old rats LPS for 24 hr NLRP3↑, ASC↑, Caspase-1↑, IL-1β↑, IL-6↑, TNF-α↑ - [39]
Primary microglia from postnatal day-1 rat LPS and serum amyloid A protein for 1–24 hr NLRP3 ↑, IL-1β ↑ P2X7R [40]
A microglial cell line derived from C57BL/6 mice (NR-9460) NMEC RS218 IL-1β↑, IL-1α↑ TLR4/Myd88 [41]
Primary mouse cortical astrocytes from P0 mice OGD NLRP3↑, ASC↑, Caspase-1↑, TNF-α↑, IL-1β↑, IL-6↑, IL-10↑ JAK2-STAT3 [42]
Rat hippocampal astrocytes from 1-day-old rats OGD NLRP3↑, ASC↑, Caspase-1↑, GSDMD↑, IL-1β↑, IL-18↑ miRNA-148a-3p [43]
STAT/JMJD3 axis
Primary cortical astrocytes from 3-day-old rats Unconjugated bilirubin for 6 and 12 hr Caspase-1 ↑, NLRP3 ↑, IL-1β ↑, IL-18 ↑ - [44]
PC12 rat pheochromocytoma cells OGD NLRP3↑, ASC↑, GSDMD↑, IL-1β↑, IL-18↑ - [46]
PC12 rat pheochromocytoma cells CoCl2 for 24 hr NLRP3↑, ASC↑, Caspase-1↑, TNF-α↑ , IL-1β↑, IL-6↑, IL-18↑, NfκB↑ - [22]
PC12 rat pheochromocytoma cells OGD NLRP3↑, ASC↑, Caspase-1↑ - [47]
Primary neuron culture from D18 rat fetus brain OGD Caspase-1 ↑, NLRP3 ↑, IL-1β ↑ - [48]

ASC, apoptosis-associated speck-like protein containing a Caspase recruitment domain; GSDMD, Gasdermin D; HMGB1, high mobility group box 1; IL, interleukin; LPS, lipopolysaccharide; NF-κB, nuclear factor κB; NLRP3, NOD-like receptor family pyrin domain containing 3; NMEC, neonatal meningitis-associated Escherichia coli; OGD, oxygen/glucose deprivation; TNF-α, tumor necrosis factor-alpha.

Table 2.

Mechanisms of action of in vivo models of hypoxia-induced NLRP3 inflammasome activation

Model Outcome Pathway References
Neonatal HIBD in mice NLRP3 ↑ [49]
Neonatal HIBD in NLRP3‒/‒ and ASC‒/‒ mice NLRP3‒/‒ mice had more activated microglia than Wt mice, but ASC‒/‒ animals had less active microglia - [50]
Neonatal HIBD in a rat model with, NLRP3 inhibitor MCC950, NLRP3 inhibitor, significantly reduced pyroptosis in a rat model of neonatal HIBD - [21]
Neonatal rat model of inflammation-sensitized HIBD IL-1β, IL-6, iNOS, and TNF-α, Arg1, CCL11, IL-1, and TGF-β and NLRP3↑ in sorted CD11b/c microglia of brain samples - [51, 52]
Neonatal HIBD in a rat model Caspase-1, IL-1β, IL-18↑ - [51, 52]
NLRP3 expression ↑ at 6 hr to 24 hr after HI, which declined 48 h after HI.
Neonatal HIBD model with Gingko Biloba IL-1β, IL-18↑ - [56]
NLRP3↑
Caspase-1 and the nuclear translocation of NFκB P65↑
Neonatal HIBD in a rat model with IRE1α inhibitor TXNIP/NLRP3 inflammasome activation TXNIP/NLRP3 - miR-17-5p [57]
White matter damage (WMD) caused by endotoxin and ischemic hypoxia in neonatal rats NLRP3, IL-1β and IL-18 ↑ TLR4/NFκ-B pathway [58]
Neonatal HIBD in a rat model with N-acetylserotonin derivative NLRP3↑ PI3K/Akt/Nrf2 pathway [59]
Neonatal HIBD in a rat model with neferine Caspase-1, ASC, GSDMD, TNFα, IL-β, IL-18, IL-6 ↑ - [22]
HI-induced model of cerebral white matter damage (WMD) NLRP3, Caspase-1, IL-1β, TNFα, IL10 ↑ - [48, 51-55]
HI-induced model of cerebral white matter damage (WMD) with caffeine NLRP3 inflammasome activation in neonatal rats - [54]
Neonatal rat model of inflammation-sensitized HIBD NLRP3, CXCL1 and CXCR2↑ CXCL1/CXCR2 pathway [43, 60]
Neonatal HIBD in a rat model with Dexmedetomidine IL-1β and IL-18 cytokine levels and NLRP3, ASC, Caspase-1, GSDMD ↑ - [43]
Rat model of neonatal sepsis with rCC16 (recombinant club cell protein) NLRP3, Caspase-1, TNFα, IL-1β and IL-6 levels, phosphorylated p38-MAPK and ERK ↑ - [63]
HI in Wt and Nrf2‒/‒ mice NFκB and NLRP3↑ - [61]
Neonatal HIBD in a rat model with maternal treadmill exercise NLRP3, Caspase-1 ↑ - [53]
Neonatal hyperoxia in mice NLRP3, IL-1β, Caspase-1 ↑ - [37]
Neonatal bilirubin-induced neuronal damage (BIND) model in rats with rapamycin NLRP3 and ASC protein ↑ - [36]
Neonatal BIND model in Nlrp3‒/‒, Caspase-1‒/‒ and WT mice NLRP3, Caspase-1 and IL-1β↑ - [37]
Diminished in knockouts
Neonatal meningitis-associated Escherichia coli (NMEC). NLRP3‒/‒ and Caspase-1‒/‒ mice IL-1b and IL-1a ↑ - [41]
Diminished in knockouts
Neonatal encephalopathy (NE) patients IL-1ra, IL-18, NLRP3 and IL-1 ↑ - [64]
Mice model of preterm brain injury NLRP3 and IL-1β ↑ - [62]

ASC, apoptosis-associated speck-like protein containing a Caspase recruitment domain; CXCL1, chemokine (C-X-C motif) ligand 1; CXCR2, C-X-C chemokine receptor 2; ERK, extracellular signal-related kinase; GSDMD, Gasdermin D; HI, hypoxia-ischemia; HIBD, hypoxia-induced brain death; IL, interleukin; iNOS, inducible nitric oxide synthase; MAPK, mitogen-activated protein kinase; NF-κB, nuclear factor κB; NLRP3, NOD-like receptor family pyrin domain containing 3; TGF-β, transforming growth factor-beta; TNF-α, tumor necrosis factor-alpha, TXNIP, thioredoxin-interacting protein; Wt, wild-type.

Table 3.

Potential preventive or therapeutic reagents used in in vitro, in vivo and clinical studies mentioned in this article

Study type Reagents Mechanism of action References
In vitro Glycyrrhizin HMG1 inhibitor [24]
Rapamycin mTOR inhibitor [36]
NLRP3 siRNA siRNA [37]
miR-374a-5p mimic Targeting Smad6 [20]
Osteopontin Secretory extracellular matrix glycoprotein [39]
A740003 P2X7R antagonist [40]
MCC950 NLRP3 inhibitor [41]
ZJU37 RIP1/RIP3 inhibitor [68]
Dexmedetomidine α2-adrenoceptor agonist [43]
VX-765 Caspase-1 inhibitor [44]
HIBDAP Pyroptosis suppressor [47]
Diallyl disulfide Pyroptosis suppressor [46]
In vivo Gingko Biloba NLRP3 supressor [56]
miR-17-5p IRE1α supressor [57]
MCC950 NLRP3 inhibitor [21]
Melatonin TLR4/NF-κB pathway inhibitor [58]
N-acetylserotonin PI3K/Akt/Nrf2 pathway activator [59]
Neferine NLRP3 inflammasome activation supressor [22]
Caffeine A2aR antagonist [54]
Dexmedetomidine α2-adrenoceptor agonist [43, 60]
Hydrogen Activator of Nrf2-mediated NLRP3 and NF-κB pathways [61]
rCC16 Pyroptosis suppressor [63]
Clinic Anakinra IL-1 receptor antagonist [67]

HMG1, high mobility group 1; IL, interleukin; IRE1, inositol-requiring transmembrane kinase/endoribonuclease 1α; mTOR, mammalian target of rapamycin; NF-κB, nuclear factor κB; NLRP3, NOD-like receptor family pyrin domain containing 3; PI3K, phosphoinositide 3-kinase; RIP1, receptor-interacting protein 1; RIP3, receptorinteracting protein 3; siRNA, small interfering RNA; TLR4, Toll-like receptor 4.