Inhibition Of Inflammasome Research Articles

Interrogating direct NLRP3 engagement and functional inflammasome inhibition using cellular assays

As a key regulator of the innate immune system, the NLRP3 inflammasome responds to a variety of environmental insults through activation of caspase-1 and release of the proinflammatory cytokines IL-1β and IL-18. Aberrant NLRP3 inflammasome function is implicated in numerous inflammatory diseases, spurring drug discovery efforts at NLRP3 as a therapeutic target. A diverse array of small molecules is undergoing preclinical/clinical evaluation with a reported mode of action involving direct modulation of the NLRP3 pathway. However, for a subset of these ligands the functional link between live-cell target engagement and pathway inhibition has yet to be fully established. Herein we present a cohort of mechanistic assays to both query direct NLRP3 engagement in cells, and functionally interrogate different nodes of NLRP3 pathway activity. This system enabled the stratification of potency for five confirmed NLRP3 inhibitors, and identification of two reported NLRP3 inhibitors that failed to demonstrate direct pathway antagonism.

Splenic monocytes mediate inflammatory response and exacerbate myocardial ischemia/reperfusion injury in a mitochondrial cell-free DNA-TLR9-NLRP3-dependent fashion.

The spleen contributes importantly to myocardial ischemia/reperfusion (MI/R) injury. Nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) recruits inflammasomes, initiating inflammatory responses and mediating tissue injury. We hypothesize that myocardial cell-free DNA (cfDNA) activates the splenic NLRP3 inflammasome during early reperfusion, increases systemic inflammatory response, and exacerbates myocardial infarct. Mice were subjected to 40min of ischemia followed by 0, 1, 5, or 15min, or 24h of reperfusion. Splenic leukocyte adoptive transfer was performed by injecting isolated splenocytes to mice with splenectomy performed prior to left coronary artery occlusion. CY-09 (4mg/kg) was administered 5min before reperfusion. During post-ischemic reperfusion, splenic protein levels of NLRP3, cleaved caspase-1, and interleukin-1β (IL-1β) were significantly elevated and peaked (2.1 ± 0.2-, 3.4 ± 0.4-, and 3.2 ± 0.2-fold increase respectively, p < 0.05) within 5min of reperfusion. In myocardial tissue, NLRP3 was not upregulated until 24h after reperfusion. Suppression by CY09, a specific NLRP3 inflammasome inhibitor, or deficiency of NLRP3 significantly reduced myocardial infarct size (17.3% ± 4.2% and 33.2% ± 1.8% decrease respectively, p < 0.01). Adoptive transfer of NLRP3-/- splenocytes to WT mice significantly decreased infarct size compared to transfer of WT splenocytes (19.1% ± 2.8% decrease, p < 0.0001). NLRP3 was mainly activated at 5min after reperfusion in CD11b+ and LY6G- splenocytes, which significantly increased during reperfusion (24.8% ± 0.7% vs.14.3% ± 0.6%, p < 0.0001). The circulating cfDNA level significantly increased in patients undergoing cardiopulmonary bypass (CPB) (43.3 ± 5.3ng/mL, compared to pre-CPB 23.8 ± 3.5ng/mL, p < 0.01). Mitochondrial cfDNA (mt-cfDNA) contributed to NLRP3 activation in macrophages (2.1 ± 0.2-fold increase, p < 0.01), which was inhibited by a Toll-like receptor 9(TLR9) inhibitor. The NLRP3 inflammasome in splenic monocytes is activated and mediates the inflammatory response shortly after reperfusion onset, exacerbating MI/R injury in mt-cfDNA/TLR9-dependent fashion. The schema reveals splenic NLRP3 mediates the inflammatory response in macrophages and exacerbates MI/R in a mitochondrial cfDNA/ TLR9-dependent fashion.

Glycogen Synthase Kinase-3β, NLRP3 Inflammasome, and Alzheimer's Disease.

Alzheimer's disease (AD) is the most prevalent cause of dementia worldwide. Because of the progressive neurodegeneration, individual cognitive and behavioral functions are impaired, affecting the quality of life of millions of people. Although the exact pathogenesis of AD has not been fully elucidated, amyloid plaques, neurofibrillary tangles (NFTs), and sustaining neuroinflammation dominate its characteristics. As one of the major tau kinases leading to hyperphosphorylation and aggregation of tau, glycogen synthase kinase-3β (GSK-3β) has been drawing great attention in various AD studies. Another research focus of AD in recent years is the inflammasome, a multiprotein complex acting as a regulator in immunological reactions to exogenous and endogenous danger signals, of which the Nod-like receptor (NLR) family, pyrin domain-containing 3 (NLRP3) inflammasome has been studied mostly in AD and proven to play a significant role in AD development by its activation and downstream effects such as caspase-1 maturation and interleukin (IL)-1β release. Studies have shown that the NLRP3 inflammasome is activated in a GSK-3β-dependent way and that inhibition of the NLRP3 inflammasome downregulates GSK-3β, suggesting that these two important proteins are closely related. This article reviews the respective roles of GSK-3β and the NLRP3 inflammasome in AD as well as their relationship and interaction.

The Anti-Inflammatory Mediator 17(R)-Resolvin D1 Attenuates Pressure Overload-Induced Cardiac Hypertrophy and Fibrosis.

Increased inflammation contributes to pressure overload-induced myocardial remodeling. 17(R)-Resolvin D1 (17(R)-RvD1), a potent lipid mediator derived from docosahexaenoic acid, possesses anti-inflammatory and pro-resolving properties. However, the association between 17(R)-RvD1 and pressure overload-induced cardiac hypertrophy remains unclear. Transverse aortic constriction (TAC) surgery was performed to establish a cardiac hypertrophy model. C57BL/6J mice were randomly assigned to the Sham, TAC and TAC+17(R)-RvD1 groups. 17(R)-RvD1 was injected (2 μg/kg, i.p.) before TAC surgery and once every other day after surgery for 4 weeks. The same volume of saline was injected into the mice in both Sham group and TAC group. Then, cardiac function was evaluated and heart tissues were collected for biological analysis. 17(R)-RvD1 treatment attenuated TAC-induced increase in left ventricular diameter and decrease in left ventricular contractility, mitigated increased cardiomyocyte cross-sectional area, and downregulated the expression of hypertrophic genes. Besides, 17(R)-RvD1 attenuated myocardial fibrosis, as indicated by the decreased LV collagen volume and expression of fibrotic genes. In addition, 17(R)-RvD1 ameliorated the inflammatory response in cardiac tissue, as illustrated by the decreased infiltration of CD68+ macrophages and reduced production of pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6. 17(R)-RvD1 treatment significantly suppressed the activation of NLRP3 inflammasome after TAC surgery, which might be responsible for the attenuation of inflammation in cardiac tissue. 17(R)-RvD1 attenuated pressure overload-induced cardiac hypertrophy and fibrosis, and the possible mechanism may be associated with the inhibition of NLRP3 inflammasome. 17(R)-RvD1 may serve as a potential drug for the treatment of cardiac hypertrophy.

Discovery of Triazinone Derivatives as Novel, Specific, and Direct NLRP3 Inflammasome Inhibitors for the Treatment of DSS-Induced Ulcerative Colitis.

NLRP3 is an intracellular sensor protein that causes inflammasome formation and pyroptosis in response to a wide range of stimuli. Aberrant activation of NLRP3 inflammasome has been implicated in various chronic inflammatory diseases, making it a promising target for therapeutic intervention. In this work, a series of novel triazinone inhibitors of NLRP3 inflammasome were designed and synthesized. Compound L38 was identified for its excellent activity and acceptable metabolic stability among 41 compounds. Additionally, mechanism studies indicated that L38 inhibited NLRP3 inflammasome activation and pyroptosis by suppressing gasdermin D cleavage, ASC oligomerization, and NLRP3 inflammasome assembly while leaving mitochondrial ROS production, lysosome damage, and chloride/potassium efflux unaffected. Further investigation revealed that L38 could bind to the NACHT domain to exert inflammatory properties. Importantly, L38 exhibited positive therapeutic effects in DSS-induced ulcerative colitis mouse model. Taken together, this study presents a promising inhibitor of NLRP3 inflammasome deserving further investigation.

Phosphate burden induces vascular calcification through a NLRP3-caspase-1-mediated pyroptotic pathway

AimsThe aim of this study is to clarify the role of NLRP3 inflammasome in phosphate burden-induced vascular smooth muscle cell (VSMC) calcification. Main methodsVSMC calcification was induced using a high concentration of inorganic phosphate. After pharmacological inhibition or genetic silencing of the NLRP3 inflammasome, pyroptosis, or potassium efflux, the cells were examined by RT-qPCR, immunofluorescence, and western blotting to identify the NLRP3-mediated pathway for VSMC calcification. Key findingsCalcified VSMCs with α-smooth muscle actin (α-SMA) disarray presented features of pyroptosis, including caspase-1 maturation, cleaved gasdermin D (GSDMD), and a high supernatant level of lactate dehydrogenase A. Pharmacological inhibitions of caspase-1 and pyroptosis attenuated VSMC calcification, whereas interleukin-1β receptor antagonism did not. Unlike canonical NLRP3 activation, osteogenic VSMCs did not upregulate NLRP3 expression. However, NLRP3 genetic silencing or inhibitions, which targets different domains of the NLRP3 protein, could ameliorate VSMC calcification by aborting caspase-1 and GSDMD activation. Furthermore, potassium efflux through the inward-rectifier potassium channel, and not through the P2X7 receptor, triggered NLRP3 inflammasome activation and VSMC calcification. SignificanceIn the present study, we identified a potassium efflux-triggered NLRP3-caspase-1-mediated pyroptotic pathway for VSMC calcification that is unique and different from the canonical NLRP3 inflammasome activation. Therefore, targeting this pathway may serve as a novel therapeutic strategy for vascular calcification.

IDO-Kynurenine pathway mediates NLRP3 inflammasome activation-induced postoperative cognitive impairment in aged mice

Aim Postoperative cognitive dysfunction (POCD) is a common postoperative complication, especially in elderly patients. It extends hospital stay, increases the mortality rate and are heavy burdens to the family and society. Accumulating research has indicated that overactivation of pyrin domain-containing protein 3 (NLRP3) inflammasomes is related to POCD andplays a critical role in activating pro-inflammatory cytokines. According to existing studies, indoleamine 2,3-dioxygenase (IDO) is potently up-regulated by inflammatory factors, tryptophan in brain is mainly catalyzed by IDO to kynurenine (KYN), KYN metabolism may contribute to the development of depressive disorder and memory deficits. Hence, this study elucidated whether IDO-Kynurenine pathway mediates NLRP3 inflammasome activation-induced postoperative cognitive impairment in aged mice. Material and Methods POCD model was established in aged C57BL/6J mice by exploratory laparotomy under isoflurane anesthesia. Learning and memory were determined using Morris water maze. Results The data showed that IDO and kynurenine aminotransferase-II (KAT-II) mRNA in hippocampus was up-regulated, and NLRP3, caspase recruitment domain (ASC), interleukin-1b (IL-1b) and IDO overexpressed, KYN levels increased after anesthesia and surgery. NLRP3 inflammasome inhibitor (MCC950) reversed NLRP3, ASC, IL-1b and IDO overexpression, and the elevation of KYN levels. To clarify the role of IDO-Kynurenine pathway in postoperative cognitive impairment, IDO inhibitor (1-methyl-Ltryptophan 1-MT) reduced the elevation of KYN and kynurenic acid (KYNA) levels, reduction of tryptophan (TRP), as well as improved learning and memory abilities. Finally, KAT-II inhibitor (PF-04859989) reduced brain KYNA levels and restored the cognitive impairment. Conclusion These results reveal that IDO-Kynurenine pathway mediates NLRP3 inflammasome activation-induced postoperative cognitive impairment.

Molybdenum and cadmium cause blood–testis barrier dysfunction through ROS-mediated NLRP3 inflammasome activation in sheep

In this study, 24 healthy male sheep were divided into four groups: the control group, Mo group (45 mg Mo·kg-1·BW), Cd group (1 mg Cd·kg-1·BW), and Mo + Cd group (45 mg Mo·kg-1·BW + 1 mg Cd·kg-1·BW). The experiment was last for 50 d. The results showed that Mo and Cd co-exposure induced histopathological changes and ultrastructural damage, decreased the mRNA and protein expression levels of BTB (blood-testis barrier)-related factors (CX-43, ZO-1, OCLN) (P < 0.05) and the T-SOD and CAT activity (P < 0.05), increased the MDA content (P < 0.05) and the proinflammatory factors levels (P < 0.05) in sheep testes. Moreover, the results showed that a sharp decline in BTB-related factors and antioxidase activity, and a significant increase in reactive oxygen species (ROS) levels (P < 0.05) and the expression levels of NLRP3 inflammasome-related factors (P < 0.05) in primary Sertoli cells (SCs) under Mo and Cd co-exposure. However, treatment with a ROS scavenger or NLRP3 inflammasome inhibitors could relieve BTB damage and oxidative injury, reduce the production of ROS (P < 0.05) and decrease the level of inflammatory factors (P < 0.05). Overall, these results indicated that Mo and Cd co-exposure reduced BTB-related protein levels and promoted ROS production and inflammatory reactions by activating the ROS/NLRP3 inflammasome pathway in sheep testes, which eventually induced reproductive toxicity.

Association of Autophagy and Inflammation with Aging

Autophagy is a catabolic process by which cells degrade damaged organelles via lysosomal degradation and recycle intracellular macromolecules and organelles to produce ATP. Autophagy clears cytosolic molecules that have a potential role in inflammasome formation. Hyperinflammation in the aging process can cause inflammasome formation that results in multiple inflammatory response-mediated diseases. Damaged mitochondria may induce oxidative stress in cells via ROS which leads to the activation of the inflammasome. Therefore, mitophagy-induced suppression of inflammasome can reduce oxidative stress. Inflammation in aging comes with diseases such as Alzheimer’s disease and Parkinson’s disease. Decreased function of autophagy in aging is the main reason behind the improper clearing of cytosolic organelles and induction of inflammation. Autophagy can slow down aging in cells and many other disorders by suppressing inflammatory genes. Also, ROS can directly activate NLRP3 and other proinflammatory pathways that increase in aging. Suppression of the NLRP3 gene which is responsible for inflammasome formation showed inhibition of the PI3K/mTOR/AKT pathway, which is directly linked to autophagy. This suppression of NLRP3 promoted longevity in cells. The interrelation between such pathway data mining from various biological databases can resolve the complex interconnection between autophagy and inflammatory pathways which can elucidate its role in aging. By using various bioinformatics tools such as DAVID and CYTOSPACE, string matching will confirm and support a relationship between the pathways. This will give a better level of understanding of interrelated pathways of autophagy, inflammation and aging.

Molecular Activation of NLRP3 Inflammasome by Particles and Crystals: A Continuing Challenge of Immunology and Toxicology.

Particles and crystals constitute a unique class of toxic agents that humans are constantly exposed to both endogenously and from the environment. Deposition of particulates in the body is associated with a range of diseases and toxicity. The mechanism by which particulates cause disease remains poorly understood due to the lack of mechanistic insights into particle-biological interactions. Recent research has revealed that many particles and crystals activate the NLRP3 inflammasome, an intracellular pattern-recognition receptor. Activated NLRP3 forms a supramolecular complex with an adaptor protein to activate caspase 1, which in turn activates IL-1β and IL-18 to instigate inflammation. Genetic ablation and pharmacological inhibition of the NLRP3 inflammasome dampen inflammatory responses to particulates. Nonetheless, how particulates activate NLRP3 remains a challenging question. From this perspective, we discuss our current understanding of and progress on revealing the function and mode of action of the NLRP3 inflammasome in mediating adaptive and pathologic responses to particulates in health and disease.

Inhibiting the NLRP3 Inflammasome with MCC950 Alleviates Neurological Impairment in the Brain of EAE Mice

Multiple sclerosis (MS) is a chronic disease that is characterized by demyelination and neuronal damage. Experimental autoimmune encephalomyelitis (EAE) mice are used to model the disease progression of MS and mirror MS-like pathology. Previous researches have confirmed that inhibition of NLRP3 inflammasome significantly alleviated the severity of EAE mice and the demyelination of spinal cord, but its effect on neuronal damage and oligodendrocyte loss in the brain remains unclear. In this study, female C57BL/6 mice were immunized with MOG35–55 and PTX to establish experimental autoimmune encephalomyelitis (EAE) model. MCC950, a selective NLRP3 inflammasome inhibitor, was used to investigate the effect of NLRP3 inflammasome on the pathological changes and glial cell activation in the brain of EAE mice by immunohistochemistry. Our results demonstrated that MCC950 ameliorated the neuronal damage, demyelination, and oligodendrocyte loss in the brain of EAE mice. This protective effect of MCC950 may be attributed to its ability to suppress the activation of glial cells and prevents microglia polarization to M1 phenotype. Our work indicates that inhibition of NLRP3 inflammasome has the therapeutic effects of neuroprotection through immunomodulation and is a promising therapeutic strategy for MS.

Novel Sulfonylurea-Based NLRP3 Inflammasome Inhibitor for Efficient Treatment of Nonalcoholic Steatohepatitis, Endotoxic Shock, and Colitis.

The NLRP3 inflammasome is a critical component of innate immunity involved in the pathophysiology of various inflammatory diseases. In this study, we designed and synthesized a series of NLRP3 inflammasome inhibitors based on MCC950. Specifically, we optimized the furan moiety, which is considered to be potentially associated with drug-induced liver injury. The representative inhibitor N14, 4-(2-(dimethylamino)ethyl)-N-((1,2,3,5,6,7-hexahydro-s-indacen-4-yl)carbamoyl)benzenesulfonamide, not only maintains the NLRP3 inhibitory activity of MCC950 with IC50 of 25 nM but also demonstrates improved tolerability in human hepatic cells line and mouse primary hepatocytes. In addition, N14 exhibits superior pharmacokinetic properties, with an oral bioavailability of 85.2%. In vivo studies demonstrate that N14 is more effective than MCC950 in multiple NLRP3-related animal model diseases, including nonalcoholic steatohepatitis, lethal septic shock, and colitis. Our research has provided a lead compound that directly targets the NLRP3 inflammasome and can be developed as a novel therapeutic candidate for NLRP3-driven diseases.

Infusions of beta-hydroxybutyrate, an endogenous NLRP3 inflammasome inhibitor, produce antidepressant-like effects on learned helplessness rats through BDNF-TrkB signaling and AMPA receptor activation, and strengthen learning ability

Beta-hydroxybutyrate (BHB), an endogenous NLRP3 inflammasome inhibitor, has been shown to be associated with the pathophysiology of depression in rodents. However its active mechanism has not been revealed. Herein, we probed both the pathways and brain regions involved in BHB's antidepressant-like effects in a learned helplessness (LH) rat model of depression. A single bilateral infusion of BHB into the cerebral ventricles induced the antidepressant-like effects on the LH rats. The antidepressant-like effects of BHB were blocked by the TrkB inhibitor ANA-12 and the AMPA receptor antagonist NBQX, indicating that the antidepressant-like effects of BHB involve BDNF-TrkB signaling and AMPA receptor activation. Further, infusions of BHB into the prelimbic and infralimbic portions of medial prefrontal cortex, the dentate gyrus of hippocampus, and the basolateral region of amygdala produced the antidepressant-like effects on LH rats. However, infusions of BHB into the central region of amygdala, the CA3 region of hippocampus, and the shell and core regions of nucleus accumbens had no effect. Finally, a single bilateral infusion of BHB into the cerebral ventricles of naive rats strengthened learning ability on repeated active avoidance test where saline-infused animals failed to increase avoidance responses.

Simultaneous intervention against oxidative stress and inflammation by targeting Nrf2/ARE and NLRP3 inflammasome pathway mitigates thioacetamide-induced liver fibrosis in rat.

Liver fibrosis is a typical pathological state/stage involved in most chronic liver diseases and its persistence results in cirrhosis. Inflammasomes are cytoplasmic sensors that induce inflammation in response to stress. Glibenclamide (GLB) is an USFDA-approved drug for type 2 diabetes and is reported to possess anti-inflammatory activity by inhibiting inflammatory cytokines. Dimethyl fumarate (DMF) is an USFDA-approved drug for multiple sclerosis and has been reported to activate the Nrf2/ARE pathway to maintain the cellular antioxidant balance. A total of 36 rats were randomized into six groups (n=6 each). The rats were injected with thioacetamide (TAA) 200mg/kg, intraperitoneally every third day for eight consecutive weeks to induce liver fibrosis and oral treatment of GLB 0.5mg/kg/day and DMF 25mg/kg/day, and their combinations were provided for the last four consecutive weeks. Treatment with GLB, DMF, and GLB+DMF significantly protected against TAA-mediated oxidative stress and inflammatory conditions by improving hepatic function test, triglycerides, hydroxyproline, and histopathological alterations, by inhibiting the NLRP3 inflammasome signaling and fibrogenic markers, and by activating Nrf2/ARE pathway in Wistar rats. The present results suggest that simultaneous Nrf2/ARE activation and NLRP3 inflammasome inhibition could significantly contribute to developing a novel therapy for patients with liver fibrosis.

Silibinin ameliorates deoxycholic acid-induced pyroptosis in steatotic HepG2 cells by inhibiting NLRP3 inflammasome activation

Nonalcoholic steatohepatitis (NASH) represents an inflammatory subtype of nonalcoholic fatty liver disease (NAFLD). The activation of the NOD-like receptor protein 3 (NLRP3) inflammasome triggers pyroptosis, thus propelling the progression from simple steatosis to NASH. Silibinin, a hepatoprotective compound derived from milk thistle, exerts diverse hepatoprotective effects. However, the direct impact of silibinin on NLRP3 inflammasome activation and its ability to mitigate pyroptosis remain uncertain. To address this, we utilized an in vitro model of NASH, employing HepG2 cells treated with deoxycholic acid (DCA) and free fatty acids. Subsequently, we treated these model cells with silibinin for 24 h. Our findings demonstrated that, although there were no significant changes in cellular lipid content, silibinin effectively ameliorated hepatocyte injuries. Silibinin treatment inhibited the activation of the NLRP3 inflammasome and suppressed DCA-induced pyroptosis. Additionally, molecular docking analysis revealed that silibinin exhibited a binding affinity to components of the NLRP3 inflammasome similar to that of MCC950, a selective NLRP3 inhibitor. These results suggest that silibinin may alleviate inflammation in DCA-exposed HepG2 cells by mitigating pyroptosis, possibly through its binding affinity and inhibition of the NLRP3 inflammasome. Overall, our study indicates that silibinin holds promise as a therapeutic agent for NASH by modulating pyroptosis and inhibiting NLRP3 inflammasome activation.

Abstract 009: Age-related Clonal Hematopoiesis Predisposes To Hypertension In Mice Through An Inflammasome Mechanism

Hypertension incidence increases with age and represents one of the most prevalent risk factors for cardiovascular disease (CVD). Clonal events in the hematopoietic system resulting from somatic mutations in “driver” genes such as Tet2 are prevalent in elderly individuals in the absence of overt hematologic disorders. This condition is referred to as age-related clonal hematopoiesis (ARCH), and it is a newly recognized risk factor for CVD. It is unknown whether ARCH and hypertension in the elderly are causally related and, if so, what are the mechanistic features. Objective: Given that the aging process increases the prevalence of hypertension and ARCH, the current experimental study was designed to test the effect of ARCH in hypertension incidence. Methods and Results: A murine model of adoptive bone marrow transplantation to nonconditioned mice was employed to examine the interplay between ARCH and hypertension. Mice carrying Tet2-deficiency in hematopoietic cells resulted in elevated systolic (SBP) and diastolic blood pressure (DBP) as early as one day after challenge with a sub-pressure dose of angiotensin II (Ang II) 200ng/kg/min; SBP (day 1 Tet2 -/- : 148 mmHg± 4 vs. WT: 129±2 mmHg, P=0.002); day 9 Tet2 -/- 159±7 mmHg vs. WT: 139±5 mmHg, P&lt;0.05), and DBP (day 1, Tet2 -/- : 108 ±3 mmHg vs. WT: 100±1 mmHg, P&lt;0.005; day 9, Tet2 -/- : 111 ±4 mmHg vs. WT 107±3 mmHg). The ARCH Tet2 model of CH led to greater macrophage infiltration in the kidney, aorta and mesentery after Ang II compared with WT-treated mice. The Tet2-/- CH condition led to renal NLRP3 inflammasome activation and elevated renal levels of IL (interleukin)-1β (Tet2 -/- 1.4 vs. WT: 0.96, P&lt;0.005) and IL-18 (Tet2 -/- 1.56 vs. WT: 1.18, P&lt;0.005) after Ang II administration. Interestingly, administration of the inflammasome inhibitor MCC950 reversed hypertension seen in the mouse model of Tet2 -/- CH. Conclusion: Our data show that a sub-pressor dose of Ang II promotes hypertension due to elevated renal immune cell infiltration in a Tet2-CH model, promoting IL1-β and IL-18. These data suggest that Tet2 -/- CH carriers could be at elevated risk for the development of hypertension, and that NLRP3 inhibitors could be useful for treating hypertension in this population.

Effects of Blocking NLRP3 Inflammasome on Type II Innate Lymphoid Cell Response in Allergic Rhinitis.

Type 2 innate lymphoid cells (ILC2s) and NLRP3 inflammasome are related to allergic and inflammatory responses. NLRP3 inflammasome inhibitor MCC950 was demonstrated to ameliorate allergic rhinitis (AR) in animal models. To elucidate the effect of MCC950 on ILC2 responses in AR. NLRP3 inflammasome, ILC2s, IL-5+ILC2s, IL-13+ILC2s, and Th2-related factors were examined in 30 AR patients. ILC2s were identified as Lin-CRTH2+CD127+lymphocytes. ILC2s isolated from PBMCs were stimulated with LPS plus ATP. The effect of MCC950, IL-1β, and IL-18 on ILC2 responses was detected by flow cytometry. AR models were established in 60 BALB/c mice. Nasal symptoms and ILC2 responses in the AR models after MCC950 treatment were detected. Human nasal epithelial cells were stimulated with IL-13 (10 ng/mL) and treated with MCC950 (10 μM). AR patients showed activated NLRP3 inflammasome and increased ILC2 responses compared to controls. NLRP3 inflammasome levels in the AR patients were positively related to the proportion of ILC2s, IL-5+ILC2s, and IL-13+ILC2s in total PBMCs. MCC950 treatment or IL-1β/IL-18 suppression inhibited ILC2 proliferation and Th2-related factors (GATA3, RORα, IL-5, and IL-13). MCC950 administration alleviated frequencies of nasal rubbing and sneezes in the AR models. ILC2s, IL-5+ILC2s, and IL-13+ILC2s in mice were reduced by MCC950. MCC950 inhibited NLRP3 inflammasome in the in vitro models of AR. MCC950 inhibited ILC2 responses in AR and mice models, suggesting that blocking NLRP3 inflammasome may be a promising target for AR clinical treatment.

Xin-Li formula attenuates heart failure induced by a combination of hyperlipidemia and myocardial infarction in rats via Treg immunomodulation and NLRP3 inflammasome inhibition.

Heart failure (HF) is a complex clinical syndrome that represents the end result of several pathophysiologic processes. Despite a dramatic evolution in diagnosis and management of HF, most patients eventually become resistant to therapy. Xin-Li Formula (XLF) is a Chinese medicine formula which shows great potential in the treatment of HF according to our previous studies. The present study was designed to investigate the effects of XLF on HF induced by a combination of hyperlipidemia and myocardial infarction (MI) in rats and reveal the underlying mechanism. A rat model of HF induced by hyperlipidemia and MI was established with intragastric administration of XLF and Perindopril. Invitro, CD4+ T cells from mouse spleen and LPS/ATP-stimulated THP-1 macrophages were employed. XLF was shown to have markedly protective effects on MI-induced HF with hyperlipidemia in rats, including improvement of left ventricular function, reduction of left ventricular fibrosis and infarct size. Moreover, XLF administration significantly increased the number of Foxp3+ Tregs, and inhibited mTOR phosphorylation and NLRP3 signaling pathway. Invitro, we found that XLF had induced Treg activation via the inhibition of mTOR phosphorylation in CD4+ T cells. Additionally, XLF inhibited NLRP3 inflammasome activation in LPS/ATP-stimulated THP-1 macrophages. Taken together, this study raises the exciting possibility that Xin-Li Formula may benefit HF patients due to its immunomodulatory and anti-inflammatory effects via Treg activation and NLRP3 inflammasome inhibition.

A Review on Inflammasomes and Immune Checkpoints in Pre-Eclampsia Complicated with Tuberculosis and Human Immune Deficiency Virus.

The current review evaluates how inflammasomes and immune checkpoints are regulated in pre-eclampsia (PE) associated with tuberculosis (TB) and Human Immune Deficiency Virus (HIV). Studies indicate that inflammasomes such as (NRLP3, NEK7, and AIM2) and immune checkpoints such as (CLT4, PD-1, TIM3, and LAG-3) are dysregulated in TB- and HIV-infected individuals, and also in pre-eclamptic pregnancies, which explains why pregnant women who are either infected with TB or HIV have an increased risk of developing PE. Evidence suggests that inhibition of inflammasomes and immune checkpoints may assist in the development of novel anti-inflammatory drugs for the prevention and management of PE in patients with or without TB and HIV infection.

Restraint Stress-Induced Immunosuppression Is Associated with Concurrent Macrophage Pyroptosis Cell Death in Mice.

Psychological stress is widely acknowledged as a major contributor to immunosuppression, rendering individuals more susceptible to various diseases. The complex interplay between the nervous, endocrine, and immune systems underlies stress-induced immunosuppression. However, the underlying mechanisms of psychological-stress-induced immunosuppression remain unclear. In this study, we utilized a restraint stress mouse model known for its suitability in investigating physiological regulations during psychological stress. Comparing it with cold exposure, we observed markedly elevated levels of stress hormones corticosterone and cortisol in the plasma of mice subjected to restraint stress. Furthermore, restraint-stress-induced immunosuppression differed from the intravenous immunoglobulin-like immunosuppression observed in cold exposure, with restraint stress leading to increased macrophage cell death in the spleen. Suppression of pyroptosis through treatments of inflammasome inhibitors markedly ameliorated restraint-stress-induced spleen infiltration and pyroptosis cell death of macrophages in mice. These findings suggest that the macrophage pyroptosis associated with restraint stress may contribute to its immunosuppressive effects. These insights have implications for the development of treatments targeting stress-induced immunosuppression, emphasizing the need for further investigation into the underlying mechanisms.