The NLRP3 inflammasome is pivotal in the development of numerous diseases, spanning neurodegenerative conditions such as multiple sclerosis, Alzheimer’s, and Parkinson’s diseases, as well as metabolic disorders like atherosclerosis, type 2 diabetes, and obesity (18). The NLRP3 inflammasome is a multiprotein complex typically composed of the NLRP3 sensor, the ASC (apoptosis-associated speck-like protein), and the pro-caspase-1 precursor ( Figure 1 ) (19). NLRP3 is a complex multi-domain protein, consisting of three main components: the N-terminal pyrin domain (PYD), the central nucleotide-binding and oligomerization domain (NACHT), and the C-terminal leucine-rich repeat (LRR) region. It is one of the most widely studied members of the inflammasome family (20, 21). ASC, also known as PYCARD, is a protein containing an N-terminal PYD and a C-terminal caspase recruitment domain (CARD). It promotes the activation of caspase-1 (22). Pro-caspase-1 consists of two main domains: the CARD and the caspase activation domain (23).In the absence of immune activation signals, an autoinhibitory interaction between the NACHT domain and the LRR domain effectively prevents the binding of NLRP3 to ASC, thereby inhibiting the formation of the inflammasome (24). Upon detection of danger signals, the PYD domain of NLRP3 binds to ASC, which in turn recruits caspase-1 through its CARD domain, leading to the assembly of the NLRP3 inflammasome. This multiprotein complex activates pro-caspase-1 via autocatalytic cleavage, leading to the generation of active caspase-1. Active caspase-1 cleaves the precursor forms of the cytokines IL-1β and IL-18, producing their active forms. These activated cytokines play a crucial mediatory role in the inflammatory response (19, 24, 25).

The activation of the NLRP3 inflammasome can be triggered by various stimuli, including viruses, bacteria, fungi, pore-forming toxins, crystal substances (such as urate crystals, silica, asbestos, and alum), and extracellular ATP. These factors activate the NLRP3 inflammasome through different mechanisms, initiating a cascade of intracellular reactions (26, 27). The NLRP3 inflammasome activation can be initiated by various stimuli, including purinergic P2X7 receptor (P2X7R)-mediated potassium efflux, intracellular calcium influx, reactive oxygen species (ROS) production caused by mitochondrial stress, the secretion of mitochondrial DNA or cardiolipin from mitochondria, and the release of cathepsin B following lysosomal rupture (25, 27). The activation of the inflammasome is a process involving two stages: the initial priming signals and the subsequent activation signals ( Figure 1 ). In the priming signals, Toll-like receptors (TLRs) are capable of recognizing pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs), which in turn trigger the nuclear factor kappa B (NF-κB) signaling pathway activation. The activation of NF-κB promotes its translocation to the nucleus, where it binds to DNA, thereby enhancing the transcriptional expression of NLRP3, pro-IL-1β, and pro-IL-18 (24, 28). Various factors, including TNF, IL-1, high-mobility group box 1 (HMGB1), interferon (IFN), transforming growth factor-β (TGF-β), and lipopolysaccharide (LPS), can promote the priming signals of NLRP3 inflammasome activation. These molecules play crucial roles in triggering the NF-κB signaling pathway, which leads to the upregulation of key inflammasome components and preparing the system for subsequent activation (29, 30). During the activation signals, NLRP3 undergoes oligomerization, forming a complex consisting of NLRP3, ASC, and pro-caspase-1. The formation of this complex promotes the autocatalytic maturation of pro-caspase-1 into active caspase-1, which then cleaves the precursors of IL-1β and IL-18 into their biologically active mature forms (31–33). Recent studies have established an important link between the NLRP3 inflammasome and the inflammatory response triggered in ICH (34). After ICH, various upstream signals can activate the NLRP3 inflammasome, with heme, released during hemoglobin degradation, playing a crucial role (35). Following ICH, the NLRP3 inflammasome activation exacerbates both the degree of cerebral edema and the neuroinflammatory response (36).

Microglia play a critical immune regulatory role in the central nervous system (CNS), which is vital for both the physiological and pathological processes of neuroinflammation (37). The pathological characteristics of neuroinflammation are usually marked by an increase in pro-inflammatory cytokine expression, enhanced activation of microglia, infiltration of peripheral immune cells like leukocytes into neural tissue, and subsequent structural and functional damage to the nervous system (38). Microglia-mediated neuroinflammation is crucial in the inflammatory injury process. Upon activation, microglia transition from their branched morphology to an amoeboid shape, enhancing their phagocytic activity and reactivity (9, 39). M1-like microglia are characterized by a pro-inflammatory and neurotoxic phenotype, marked by the secretion of TNF-α, IL-1β, IL-12, and inducible nitric oxide synthase (INOS). These factors contribute to the exacerbation of neuroinflammation and the progression of tissue damage (40–42). M2 microglia secrete anti-inflammatory factors, suppress immune responses, and promote tissue repair and neuroregeneration. These functions are crucial for alleviating inflammation and aiding recovery after brain injury. They stimulate the release of anti-inflammatory cytokines, such as IL-4, IL-10, IL-13, and transforming growth factor-β (TGF-β), and are characterized by markers like arginase-1 (Arg-1) and CD206, which contribute to the repair process (40, 42). Simultaneously, M2 microglia facilitate axonal regeneration and vascular remodeling by secreting remodeling factors such as vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor (BDNF), which play crucial roles in tissue repair and neurovascular recovery (43). Furthermore, during the remodeling phase following a stroke, microglia and infiltrating macrophages function as essential phagocytic cell populations, collaborating to clear dead cells and tissue debris, thus facilitating the repair and reconstruction of damaged neural tissues (44). ICH may benefit from the exploration of cell therapies that target microglial phenotype switching, potentially improving patient outcomes. (There seems to be controversy regarding the M1/M2 classification of microglia, with some scholars arguing that such a classification is overly simplistic (45). However, this classification is widely used and still plays a role in understanding the functions of microglia in brain hemorrhage).

The NLRP3 inflammasome is crucial in microglia-mediated neuroinflammation after ICH and is predominantly expressed in microglia (34). Studies have shown that pre-treatment with epigallocatechin-3-gallate (EGCG) can reduce the levels of NLRP3 inflammasome in microglia following ICH and promote the transition of microglia from M1 phenotype to M2 phenotype (46). Xia et al. experimentally demonstrated that activation of sirtuin 1 (SIRT1), a sirtuin family member, suppresses NLRP3 inflammasome signaling in microglia during subarachnoid hemorrhage (SAH). Additionally, it facilitates microglia from M1 phenotype to M2 phenotype, which could be beneficial in mitigating neuroinflammation (47). Based on the hypothesis that both SAH and ICH are classified as hemorrhagic strokes, we speculate that the activation of SIRT1 may exhibit similar therapeutic effects in the context of ICH. Although neither of the two referenced studies directly addresses the connection between the NLRP3 inflammasome and microglial polarization towards M1 or M2 phenotypes, It is reasonable to propose that the NLRP3 inflammasome may play a role in regulating this phenotypic transition in microglia. However, due to the limited amount of literature on this topic, this area remains underexplored and represents one of our future research directions.

Astrocytes, the most prevalent glial cells in the CNS, are essential for supporting neurons and maintaining brain homeostasis. In response to pathological conditions, astrocytes become activated, transforming into reactive astrocytes. This process involves cell hypertrophy and an increase in the release of neurotoxic factors, playing a critical role in the development of inflammation and neuronal damage within the central CNS (48, 49). Activated microglia possess the capacity to stimulate astrocyte activation, as well as modulate astrocyte proliferation and differentiation (34). Astrocytes can be categorized into A1 and A2 phenotypes. Much like microglia, astrocytes are capable of secreting mediators, either promoting inflammation or performing immunoregulatory functions, depending on their specific polarized phenotype (50, 51). A1 astrocytes play a pro-inflammatory role by secreting neurotoxins that induce neuronal death and the apoptosis of mature oligodendrocytes, while inhibiting processes essential for neuronal survival and synaptogenesis. In contrast, A2 astrocytes exhibit anti-inflammatory activities, upregulating anti-inflammatory genes to support neuronal survival and growth. They also contribute to glial scar formation, aid in clearing cellular debris, and promote the repair of the BBB, thus facilitating tissue recovery and regeneration following CNS injury (50, 52). (Similarly, the A1/A2 classification of astrocytes is also debated internationally, and a new consensus on the classification of astrocytes has yet to be reached (53). We hold a similar view on the A1/A2 classification of astrocytes as we do for the M1/M2 classification of microglia.) ICH triggers astrocyte activation, regulating the release of pro-inflammatory factors. Research indicates a significant increase in reactive astrocytes surrounding the hematoma within 12 to 48 hours post-ICH, suggesting their involvement in the early inflammatory response and potential contribution to both neuroprotection and neurotoxicity in the acute phase of injury (54, 55). After ICH, oxidative stress triggered by the release of hemoglobin activates astrocytes, leading to an increased expression of matrix metalloproteinase-9 (MMP-9). This contributes to the disruption of the BBB, increasing vascular permeability, which in turn exacerbates neuroinflammation and secondary brain injury (34). Following ICH, inhibiting the CD147 receptor on astrocytes has been shown to reduce MMP-9 levels in the surrounding hematoma, leading to decreased tissue degradation and improved neurological recovery. Additionally, enhancing the expression of aquaporin-4 (AQP4) on astrocytes may mitigate cerebral edema by regulating water homeostasis in the brain, thereby protecting against secondary injury and further functional decline. Therefore, modulating the activity of astrocytes may serve as a promising therapeutic approach to reduce neuroinflammation and cerebral edema following ICH. Modulating astrocyte function may help alleviate the progression of secondary brain injury and improve patient outcomes. Astrocytes also express the NLRP3 inflammasome (34). Within hypoxic-ischemic encephalopathy (HIE), transient receptor potential vanilloid 1 (TRPV1) intensifies astrocyte activation and promotes the secretion of IL-1β by astrocytes via the JAK2-STAT3 signaling pathway and activation of NLRP3 inflammasomes (56). Additionally, studies have shown that in rats with thalamic hemorrhage-induced central post-stroke pain (CPSP), around the thalamic injury area, the expression of NLRP3 is significantly increased with microglia and astrocytes activation. Thalamic administration of MCC950, a small-molecule NLRP3 inflammasome inhibitor, significantly diminishes microglia and astrocytes activation and lowers the secretion of pro-inflammatory cytokines (57). Neuroinflammation is characterized by an increase in the secretion of inflammatory mediators and microglia and astrocytes activation. The study’s findings highlight the critical interplay between astrocyte activation, the NLRP3 inflammasome, and neuroinflammation. However, research on the interaction between astrocyte activation, NLRP3 inflammasome activity, and neuroinflammation following ICH remains limited, which will be one of our future research focuses. Pyroptosis is a form of caspase-1-dependent programmed cell death, leading to the release of IL-1β and IL-18, which trigger a strong neuroinflammatory response. In a mouse model of ischemic stroke induced by middle cerebral artery occlusion (MCAO), the expression of lipocalin-2 (LCN2) in astrocytes markedly increases after 24 hours, which significantly promotes neuroinflammation. MCC950 inhibition of NLRP3 inflammasome activation reduces astrocyte pyroptosis, which is exacerbated by rLCN2 injection in mice (58). Both ICH and cerebral infarction are classified as strokes and exhibit similar pathological mechanisms. Therefore, exploring the link between astrocyte activation, NLRP3 inflammasome, and neuroinflammation in ICH could provide valuable insights for future therapeutic development.

Upon erythrocyte destruction, substantial levels of hemoglobin are released into the extracellular space, where it undergoes oxidation. The oxidized hemoglobin then releases heme, a classical DAMP. When released from hemoproteins, heme acts as a potentially harmful molecule by catalyzing the production of reactive ROS (59, 60). Given that DAMPs and ROS are upstream signals for NLRP3 inflammasome activation, it suggests that heme may be involved in its activation. Hemin, derived from hemoglobin, becomes unstable at physiological temperatures after release. Ferrous heme (Fe2+) spontaneously oxidizes to ferric heme (Fe3+), dissociating from globin, and is classified as a DAMP. Earlier studies showed that in a mouse model of ICH with hemin injection, NLRP3 and IL-1β expression levels were significantly elevated. Moreover, the synergistic interaction with N-methyl-D-aspartate receptor 1 (NMDAR1) led to the activation of NLRP3, ultimately contributing to inflammatory damage (61, 62). Memantine, an antagonist of NMDAR, inhibits nitric oxide synthase ser¹⁴¹² phosphorylation through an NMDAR-related antagonistic mechanism, thereby reducing peroxynitrite, MMP-9, and NLRP3 production, which in turn mitigates BBB disruption and neurological dysfunction (63). However, the precise mechanisms underlying NMDAR antagonism remain unclear, and this will be a focus of future research. Similarly, Weng et al. observed that administering the NMDAR antagonist MK801 reduces the expression of NLRP3 in heme-treated microglia (62). In a recent study, the injection of heme into the mouse striatum was shown to increase phosphorylation levels of extracellular signal-regulated kinase (ERK) and p38, indicating MAPK pathway activation associated with inflammation. Such activation triggers the secretion of pro-IL-1β, leading to lipid peroxidation and initiating an inflammatory response within the brain. Notably, the knockout of the NLRP3 gene in mice significantly mitigated behavioral impairments and reduced the release of inflammatory cytokines (64). These results imply that heme triggers neuroinflammation through a pathway reliant on NLRP3 activation. Lin et al. additionally found that in a mouse model of ICH, heme amplified microglial activation through TLR4, which in turn triggered NF-κB activation via the TLR4/MyD88/TRIF pathway, thus exacerbating inflammatory damage (65). The study did not thoroughly investigate whether the TLR4/MyD88/TRIF signaling pathway, following the activation of NF-κB, participates in the upregulation process of NLRP3. Given the upregulation of NLRP3 by NF-κB in the priming signals of inflammasome activation, we hypothesize that heme may promote the expression of NLRP3 through this pathway. Nevertheless, further research is required to validate this hypothesis. However, a previous study appears to contradict the conclusions of the aforementioned research. Tan et al. observed that while hemin-treated primary microglial cells could promote the activation of NLRP3 inflammasome and caspase-1, there was no corresponding increase in IL-1β secretion (61). Although the role of heme in activating the NLRP3 inflammasome has been relatively well-studied, the precise connection between NLRP3 activation and the subsequent secretion of inflammatory cytokines remains an unresolved issue in current research. Therefore, further investigation in future experiments is necessary to explore this relationship in greater detail. While collagenase and autologous blood injection are the standard methods for modeling ICH, the study suggests that heme injection may offer a novel model for exploring post-ICH neuroinflammation.

Dopamine is a monoamine neurotransmitter classified within the catecholamine family. It is essential for the regulation of motor function, behavior, endocrine responses, and cardiovascular activity, and acts as a critical link between the nervous and immune systems (66, 67). Yan et al. showed that dopamine regulates systemic inflammation through suppressing NLRP3 inflammasome activation in the hippocampus. Dopamine D1 receptor (DRD1) signaling mediates a negative regulation of hippocampal NLRP3 via the second messenger cyclic adenosine monophosphate (cAMP). This pathway promotes the ubiquitination of NLRP3 by the E3 ubiquitin ligase MARCH7, resulting in NLRP3 degradation and, consequently, controlling the inflammatory response both locally and systemically (67). In a mouse model of ICH, activation of DRD1 was found to suppress microglial activation and downregulate the expression of NLRP3, caspase-1, and IL-1β, while upregulating IFN-β. This modulation significantly reduced NLRP3-driven inflammatory responses, attenuated cerebral edema, and improved neurological outcomes (68). IFN-β is a well-known immunoregulatory cytokine, recognized for its potent anti-inflammatory effect. IFN-β inhibits NLRP3 inflammasome activation and promotes T cell polarization through STAT1 phosphorylation to exert these effects (69, 70).

However, the specific mechanism by which dopamine induces the upregulation of IFN-β was not addressed in the study. Investigating this regulatory pathway in future studies may provide valuable insights for more effectively managing inflammation associated with ICH.

The endoplasmic reticulum (ER), a vital organelle within the cell, fulfills several essential functions, including lipid biosynthesis, promoting protein folding and maturation, and regulating intracellular calcium homeostasis. After ICH, ER stress is induced, which is closely associated with NLRP3 inflammasome activation (71). In obese mice, ER stress triggers the activation of key proteins such as protein kinase RNA-like ER kinase (PERK) and inositol-requiring enzyme-1α (IRE1α), which subsequently activate the NLRP3 inflammasome. This activation results in an increase in caspase-1 expression, which in turn triggers pyroptotic cell death (72). In summary, NLRP3 inflammasome activation induced by ER stress requires both PERK and IRE1 (71). Studies have shown that tauroursodeoxycholic acid (TUDCA) can inhibit ER stress, reducing NLRP3 inflammasome activation and the expression of inflammatory markers in the ICH model (73). Recent studies have also indicated that Peroxiredoxin II reduces neuroinflammation after intracerebral hemorrhage by alleviating neuronal pyroptosis and suppressing NLRP3 inflammasome activation through counteracting ER stress via the PI3K/AKT pathway (74). While research on ER stress-induced inflammasome activation in ICH remains limited, current evidence suggests that targeting ER stress could offer a promising therapeutic approach to reduce post-hemorrhagic inflammation.

After ICH, high mobility group box 1 (HMGB1) is released from the nucleus into the cytoplasm, where it interacts with toll-like receptors (TLRs) on immune cells, initiating an inflammatory cascade. Experimental studies have demonstrated that knocking down HMGB1 or TLR4 significantly reduces associated neurological impairments (75). In a rat model of ICH, elevated expression of NLRP3 inflammasome and IL-1β were observed. Notably, inhibition of HMGB1 or TLR4 led to a substantial decrease in NLRP3 expression (76). Although this study did not address whether the HMGB1/TLR4 axis activates NF-κB expression, previous research has shown that intraperitoneal injection of ethyl pyruvate in diabetic ICH mice can reduce the level of NLRP3 inflammasome via the HMGB1/TLR4 pathway, while concurrently inhibiting NF-κB activation, thereby alleviating neuroinflammation (77). A series of studies have demonstrated that NLRP3, IL-1β are target genes of NF-κB (30, 78). Based on this evidence, we hypothesize that the HMGB1/TLR4 pathway promotes NLRP3 expression through NF-κB activation, exacerbating neuroinflammation following intracerebral hemorrhage. Although there is currently limited research on this pathway in the context of ICH, we hypothesize that targeting the HMGB1/TLR4 axis could serve as a potential therapeutic approach to mitigate post-ICH inflammation. Further studies are needed to validate this mechanism and its potential for improving post-ICH neurological outcomes. Similarly, another study indicated that the TLR4/MyD88 pathway can activate NF-κB, subsequently promoting NLRP3 expression. However, atorvastatin has been shown to interrupt this process, alleviating neuroinflammation following intracerebral hemorrhage (79). Taken together with the aforementioned findings, we hypothesize that directly or indirectly modulating TLR4 may serve as an effective approach for reducing neuroinflammation post-hemorrhage.

The P2Y6 receptor (P2Y6R), part of the P2Y purinergic receptor family, is extensively expressed in the nervous system. It is very important during a range of pathological processes, particularly in immune responses and inflammatory reactions (80, 81). Recent researches have indicated that following ICH, there is a significant increase in the levels of P2Y6R and NLRP3 inflammasome. P2Y6R exacerbates NLRP3-mediated cell apoptosis by activating the PI3K/AKT pathway. Furthermore, inhibition of P2Y6R decreases the expression of key inflammatory factors, highlighting its potential role in the regulation of neuroinflammation (82). Zhu et al. also discovered that a highly selective P2Y6R antagonist (compound 50) effectively suppressed NLRP3 inflammasome activation in intestinal tissues, thereby alleviating symptoms of ulcerative colitis (83). Given that both P2Y6R and P2X7R, as previously discussed, belong to the same purinergic receptor family, they may share similar mechanisms in regulating NLRP3 inflammasome activation. Alternatively, these two receptors could synergistically activate NLRP3 inflammasomes. Exploring this potential interaction may represent a promising future research direction. The development of a dual-target inhibitor capable of blocking both receptors could offer a novel therapeutic approach to mitigate neuroinflammation after ICH.

In rats with ICH, complement activation was first demonstrated, revealing its involvement in promoting brain edema and injury through multiple pathways (84). Complement is closely linked to inflammation in ICH, with the complement cascade representing the initial phase of sterile inflammation (85). Recent research has shown that during ICH-induced neuroinflammation, the levels of complement components C3a and C5a are elevated, and their supplementation can induce IL-1β expression. In contrast, inhibiting NLRP3 mitigates this effect, highlighting the crucial role of NLRP3 in complement-mediated neuroinflammation after ICH (86). However, studies in this area remain limited, and the precise mechanisms connecting complement activation with NLRP3 inflammasome activation have yet to be fully elucidated.

Autophagy serves as a highly conserved cellular mechanism, playing an essential role in the removal of damaged, aging, or surplus cytoplasmic components, directing them to lysosomes for degradation and recycling. Mitophagy, a specialized subtype of autophagy, is tasked with the selective removal of impaired or malfunctioning mitochondria via lysosomal degradation. Emerging studies indicate that mitophagy helps to inhibit NLRP3 inflammasome activation, thereby regulating inflammatory responses (131, 132). FUN14 domain containing 1 (FUNDC1) is a key mitophagy receptor. Zheng and colleagues demonstrated that FUNDC1 mitigates neuroinflammation following ICH by promoting mitophagy, which in turn suppresses the expression of NLRP3 inflammasome (133). Studies have also found that Nrf2 interacts with the mitochondrial autophagy receptor optineurin (OPTN), regulating mitophagy to clear dysfunctional mitochondria following intracerebral hemorrhage (ICH). This process inhibits NLRP3 inflammasome activation, thereby reducing neuroinflammation (103).However, conflicting evidence exists, with earlier studies showing that TLR4 can activate microglia and exacerbate inflammatory damage in ICH through autophagy pathways (134). This suggests ongoing debate about the precise role of autophagy in regulating inflammation post-ICH. Despite this, numerous studies have indicated that both autophagy and mitophagy can attenuate inflammation after ICH (135). So further studies are needed to elucidate the detailed mechanisms underlying these effects.

Stem cell therapy offers significant promise for promoting neuroprotection and enhancing neurorecovery (136). BMSC possess multi-differentiation and self-renewal abilities, offering significant potential in treating neurological sequelae following ICH (137, 138). Extracellular vesicles derived from BMSC have demonstrated the potential to enhance neurological function, decrease brain edema, and mitigate neuroinflammation in diabetic ICH, primarily through the delivery of miR-183-5p. Mechanistically, miR-183-5p exerts its effects by targeting PDCD4 and suppressing the NLRP3 pathway (139). Furthermore, hypoxic preconditioning of mesenchymal stem cells has been shown to suppress microglial activation, decrease IL-1β and TNF-α levels, and downregulate NLRP3 and Caspase-1 expression, thereby reducing pyroptosis and neuroinflammation following ICH (140). At present, stem cell-based therapies for ICH are gaining significant attention, with various types of stem cells being explored, including mesenchymal stem cells, embryonic stem cells, hematopoietic stem cells, and neural stem cells (136). However, most studies on inhibiting neuroinflammation after ICH have concentrated on mesenchymal stem cells. In the future, we may explore the potential of different stem cell types in alleviating neuroinflammation following ICH.

We found that knocking out certain genes can also inhibit NLRP3 expression and thereby reduce neuroinflammation following ICH. Zhao et al. found that LCN2 knockout in an ICH rat model significantly diminished the secretion of inflammatory cytokines including IL-1β, IL-18, and TNF-α. Additionally, it reduced NLRP3 inflammasome expression, facilitated hematoma clearance, and alleviated brain edema and inflammatory cell infiltration (141).Additionally, the FERM domain-containing kindlin 1 (FERMT1) is an integrin-associated protein. Knocking out FERMT1 reduced brain edema after ICH, promoted hematoma clearance, and improved behavioral outcomes. FERMT1 knockout was also found to suppress NLRP3 inflammasome activation, leading to a reduction in the release of pro-inflammatory cytokines such as IL-1β and IL-18 (142). The commonly used gene editing technologies, such as CRISPR-Cas9, have developed rapidly, and successful clinical trials have already been conducted. For example, Lu et al. used CRISPR-Cas9 technology to knock out Programmed Cell Death Protein 1 (PD-1) on human T cells to treat patients with non-small cell lung cancer, demonstrating strong safety and feasibility (143). However, the clinical translation of gene editing technology still faces significant obstacles. The application of gene editing in humans raises ethical controversies, particularly in cases involving the editing of human germline cells, which could lead to severe ethical debates. Additionally, gene editing technologies carry the risk of off-target effects, where the editing tool may mistakenly cut non-target genes during DNA cleavage, potentially leading to the deletion of essential genes and causing severe consequences. Therefore, the effectiveness of specific gene knockout treatments for post-ICH neuroinflammation remains to be determined.

Studies have shown that cathepsin B (CTSB) is crucial in regulating NLRP3 expression. The activation of the CTSB/NLRP3 signaling pathway exacerbates neurological damage, especially in cases of hippocampal injury (144). In a study conducted on rats with ICH, Zhou et al. reported that Cystatin C effectively inhibits CTSB-mediated activation of the NLRP3 inflammasome within microglia, consequently mitigating secondary brain damage after ICH (16). Oxytocin (OXT), secreted by neurons in the hypothalamus, plays a multifunctional role by promoting parturition and exhibiting anti-inflammatory and antioxidant properties through the stimulation of oxytocin receptors (OXTR). Yang et al. found that following ICH, endogenous OXT levels were decreased, while the expression of OXTR was significantly upregulated. Intranasal administration of OXT has been shown to suppress the secretion of NLRP3, caspase-1, IL-1, and IL-18. Mechanistically, OXT exerts its neuroprotective effects and attenuates neuroinflammation after ICH through activation of the OXTR/p-PKA/DRP1 signaling pathway (145). Dendritic cell-associated C-type lectin-1 (Dectin-1) is a pattern recognition receptor known to initiate inflammatory responses. Research has shown that Dectin-1 expression significantly increases in microglia following ICH. Laminarin-mediated inhibition of Dectin-1 has been shown to downregulate the expression of NLRP3, IL-1, and IL-18. This results in a reduction of brain edema and a decrease in neurological damage after ICH, suggesting that targeting Dectin-1 could be a promising approach for alleviating neuroinflammation and improving outcomes following ICH (146). Protein tyrosine phosphatase non-receptor type 22 (PTPN22) has been linked to the development of several inflammatory disorders. It plays a role in enhancing NLRP3 inflammasome activation and promoting the release of IL-1β, contributing to the inflammatory response (147). Wang et al. demonstrated that histone deacetylase 10 (HDAC10) can mitigate neuroinflammation after ICH by blocking the interaction between PTPN22 and NLRP3. This inhibition prevents inflammasome activation and reduces the inflammatory damage that follows (148).