NLRP3 Inhibitor Research Articles

The dual-targeting mechanism of an anti-inflammatory diarylheptanoid from Curcuma zedoaria (Christm.) Roscoe with the capacity for β2-adrenoreceptor agonism and NLRP3 inhibition

Chronic obstructive pulmonary disease (COPD) is a common respiratory disease characterized by symptoms of shortness of breath and chronic inflammation. Curcuma zedoaria (Christm.) Roscoe is a well-documented traditional medical herb that is frequently used in the treatment of COPD. Previously, we identified a diarylheptanoid compound (1-(4-hydroxy-5-methoxyphenyl)-7-(4,5-dihydroxyphenyl)-3,5-dihydroxyheptane; abbreviated as HMDD) from this herb that exhibited potent agonistic activity on β2-adrenergic receptors (β2 adrenoreceptor) that are present on airway smooth muscle cells. In this work, we used chemically synthesized HMDD compound, and confirmed its bioactivity on β2 adrenoreceptors. Then by a proteomics study and anti-inflammatory evaluation detections, we found that HMDD downregulated the nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) signaling pathway and suppressed the NLRP3 receptor expression in RAW264.7 macrophages and in a COPD model in A549 lung carcinoma cells. HMDD also decreased nitric oxide production levels, and impacted other interleukins and the phosphorylation of NF-κB and ERK pathways. We performed molecular docking of HMDD on β2 adrenoreceptor and NLRP3 protein models. This work reports the anti-inflammatory effects of HMDD and suggests a dual-targeting mechanism of β2-adrenoreceptor agonism and NLRP3 inhibition. Such a mechanism scientifically supports the clinical uses of Curcuma zedoaria (Christm.) Roscoe in treating COPD, as it can simultaneously relieve persistent breathlessness and inflammation. HMDD can be considered as a potential non-steroidal anti-inflammatory drug in novel therapy design for the treatment of COPD and other inflammatory diseases.

Comparison of treatment of COVID-19 with inhaled bromhexine, higher doses of colchicine and hymecromone with WHO-recommended paxlovid, molnupiravir, remdesivir, anti-IL-6 receptor antibodies and baricitinib

Millions of publications and thousands of clinical trials have not led to the discovery of an effective treatment for COVID-19. We believe that the reason for this is the inaccurate strategy of inhibiting target molecules involved in the pathogenesis of the disease. The leading cause of death in COVID-19 is the cytokine storm, which is caused by an NLRP3 inflammasome hyperreaction. WHO recommends for the outpatients treatment drugs blocking the replication of SARS-CoV-2. However, viral load and replication are not directly related to NLRP3 inflammasome hyperreactivity. This also explains the partial success of the WHO favorite paxlovid to reduce hospitalizations (51%). For hospital treatment, WHO suggests antibodies against the interleukin-6 receptor and Janus kinase (JAK) inhibition. Although important, IL-6 is one of dozens of cytokines elevated as a consequence of cytokine storm. The JAK inhibitor baricitinib inhibited the effect of not only IL-6 but also other elevated cytokines. But if the NLRP3 inflammasome is inhibited, the cytokines will not be elevated, and there will be no need for baricitinib. All medicines recommended by the WHO are distinguished by their very high prices. Our therapeutic strategy is based on inhibition of SARS-CoV-2 entry into the cell and inhibition of the NLRP3 inflammasome. We offer two readily available, cheap and well-known medications - bromhexine hydrochloride and colchicine. The many studies on the treatment of COVID-19 so far have not produced the expected result. The devil is buried in the details. For bromhexine, the reason is the way and its late application. Bromhexine is most effective when given prophylactically or started by inhalation after contact with a person with COVID-19. Its earliest possible application is crucial for its effect. Increased doses of colchicine are necessary for COVID-19 treatment due to the fact that it accumulates in leukocytes, and this leads to inhibition of NLRP3. The high doses we administer have been given widely in the past and are completely safe. Our highest dose is about 5 times lower per kg of weight than the lowest severe toxic dose of colchicine described. Our results show about a 5-fold decrease in hospital mortality and almost complete prevention of hospitalizations if outpatients are treated with inhaled bromhexine and colchicine.

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.

Sorcin regulate pyroptosis by interacting with NLRP3 inflammasomes to facilitate the progression of hepatocellular carcinoma

A high recurrence rate and easy metastasis are two prominent clinical features of hepatocellular carcinoma (HCC), which is also the most common cause of cancer-related death. However, the molecular pathogenesis of HCC remains unclear. Soluble resistance-related calcium-binding protein (Sorcin) is highly expressed in a variety of tumor cell lines and multidrug-resistant cell lines and participates in the malignant progression of tumors by regulating apoptosis. Pyroptosis is also a form of programmed cell death that plays a crucial role in exerting tumor suppression function and evoking anti-tumor immune responses. However, there is no consensus that Sorcin promotes HCC progression by regulating pyroptosis. Our study manifested that Sorcin was considerably upregulated, whereas pyroptosis-associated proteins were significantly decreased in HCC tissues and cells. Sorcin silencing attenuated the proliferation, migration, and invasion of HCC cells. Knockdown of Sorcin activates pyroptosis, and overexpression of Sorcin inhibits pyroptosis, yet has no significant effect on apoptosis, ferroptosis, and autophagy in HCC cells. Furthermore, coimmunoprecipitation and immunofluorescence assays revealed that Sorcin interacted with NLRP3 inflammasome to regulate pyroptosis in HCC cells. Then, the NLRP3 inhibitor MCC950 inhibited the activation of Sorcin knockdown-induced pyroptosis and reversed the effect of Sorcin silencing-induced weakening of malignant biological behavior in HCC. Similarly, suppression of Caspase-1 reversed the inhibitory effect of Sorcin knockdown on the malignant progression of HCC via knockdown of Caspase-1 or the inhibitor VX765. Consistent with the in vitro results, the nude mouse experiment showed that Sorcin knockdown inhibited the growth of HCC by activating pyroptosis, while Caspase-1 knockdown partially restored the growth inhibition caused by Sorcin knockdown. Collectively, high Sorcin expression in HCC negatively regulates pyroptosis by interacting with the NLRP3 inflammasome to promote HCC proliferation, migration, and invasion. The results of this study provide a scientific basis for Sorcin as a new biomarker and potential therapeutic target for HCC.

Control of Cell Death in Health and Disease.

Apoptosis, necroptosis, and pyroptosis are genetically programmed cell death mechanisms that eliminate obsolete, damaged, infected, and self-reactive cells. Apoptosis fragments cells in a manner that limits immune cell activation, whereas the lytic death programs of necroptosis and pyroptosis release proinflammatory intracellular contents. Apoptosis fine-tunes tissue architecture during mammalian development, promotes tissue homeostasis, and is crucial for averting cancer and autoimmunity. All three cell death mechanisms are deployed to thwart the spread of pathogens. Disabling regulators of cell death signaling in mice has revealed how excessive cell death can fuel acute or chronic inflammation. Here we review strategies for modulating cell death in the context of disease. For example, BCL-2 inhibitor venetoclax, an inducer of apoptosis, is approved for the treatment of certain hematologic malignancies. By contrast, inhibition of RIPK1, NLRP3, GSDMD, or NINJ1 to limit proinflammatory cell death and/or the release of large proinflammatory molecules from dying cells may benefit patients with inflammatory diseases.

Chronic kidney disease promotes atrial fibrillation via inflammasome pathway activation.

Chronic kidney disease (CKD) is associated with a higher risk of atrial fibrillation (AF). The mechanistic link between CKD and AF remains elusive. IL-1β, a main effector of NLR family pyrin domain-containing 3 (NLRP3) inflammasome activation, is a key modulator of conditions associated with inflammation, such as AF and CKD. Circulating IL-1β levels were elevated in patients with CKD who had AF (versus patients with CKD in sinus rhythm). Moreover, NLRP3 activity was enhanced in atria of patients with CKD. To elucidate the role of NLRP3/IL-1β signaling in the pathogenesis of CKD-induced AF, Nlrp3-/- and WT mice were subjected to a 2-stage subtotal nephrectomy protocol to induce CKD. Four weeks after surgery, IL-1β levels in serum and atrial tissue were increased in WT CKD (WT-CKD) mice versus sham-operated WT (WT-sham) mice. The increased susceptibility to pacing-induced AF and the longer AF duration in WT-CKD mice were associated with an abbreviated atrial effective refractory period, enlarged atria, and atrial fibrosis. Genetic inhibition of NLRP3 in Nlrp3-/- mice or neutralizing anti-IL-1β antibodies effectively reduced IL-1β levels, normalized left atrial dimensions, and reduced fibrosis and the incidence of AF. These data suggest that CKD creates a substrate for AF development by activating the NLRP3 inflammasome in atria, which is associated with structural and electrical remodeling. Neutralizing IL-1β antibodies may be beneficial in preventing CKD-induced AF.

Total alkaloids of Sophora alopecuroides alleviate atherosclerosis by regulating macrophage pyroptosis induced by reactive oxygen species-NLRP3 signaling axis

Cardiovascular and cerebrovascular diseases are common diseases. This study aimed to investigate the role of total alkaloids of Sophora alopecuroides (TASA) in atherosclerosis and exploring the underlying mechanism. Mice were given normal diet (ND), high-fat diet (HFD), and TASA plus ND or HFD. The mice were further administered with NLRP3 shRNA and shControl. After treatment, Hematoxylin and Eosin and Oil Red O staining assessed histological changes. CD31/caspase-1 double staining was detected by fluorescent staining and pyroptosis expression assessed by CD31/TUNEL double staining. Western blot results determined caspase-1 expression in HFD mice. TASA treatment suppressed plaque formation in HFD-fed ApoE-/- mice but insignificantly altered the lesion area in ND-fed ApoE-/- mice. Caspase-1 content and TUNEL positive cells were significantly elevated in mice fed with HFD or ND, whilst advent of TASA further enhanced the activation of caspase-1 in HFD mice. TASA treatment reduced activity of ROS, inhibited NLRP3 inflammasome and regulated macrophage pyroptosis. Inhibition of NLRP3 decreased the lesion area of atherosclerosis and lipid deposition. TASA inhibited the expression of ROS to reduce macrophages necrosis and secretion of inflammatory mediators, thereby alleviating inflammation, delaying plaque formation and stabilizing plaques in atherosclerosis.

Secondary Analysis of RRx-001 on the Incidence of Related Toxicities in Patients Treated with Concomitant Chemoradiation for Locally Advanced Head and Neck Cancer

The results of an open-labeled Phase 2a trial (PREVLAR) suggested that infusion of RRx-001 (bromonitrozidine), a nitrogen-containing NLRP3 inhibitor and Nrf2 activator, attenuated the course and severity of severe oral mucositis (SOM) associated CRT (cisplatin/IMRT) in cancers of the mouth or OPC without impeding tumor response.1 Given its mechanism of action and the shared biology of radiation injury pathogenesis among other exposed tissues, we investigated the potential halo effect of RRx-001 on other regimen-related toxicities. PREVLAR was a multi-center, open-label randomized trial in which patients (n = 46) having locally advanced, histologically confirmed SCC of the OC or OPC were centrally randomized to one of four arms. Arms 1-3 received 2 weekly doses of RRx-001 (4 mg/dose) beginning 2 weeks before the start of CRT. Arm 2 (n = 11) received 2 additional RRx-001 infusions during weeks 2 and 5 and patients in Arm 3 (n = 13) received weekly RRx-001 for the first 6 weeks of CRT. 10 mg of dexamethasone was administered before RRx-001 infusions. Arm 4 (n = 10), the control, received CRT only. Adverse events (AEs) were assessed using CTCAE v5. All patients received standard regimens of IMRT (daily fractions of 2-2.2 Gy/minimum cumulative dose of 55 Gy) plus either weekly or tri-weekly cisplatin. Consistent with the observation that RRx-001 was most efficacious in attenuating the course of SOM when administered only prior to CRT (Arm 1) or prior to CRT with additional dosing on weeks 2 and 5 (Arm 2), compared to Arm 3 or control, the same dosing schedule appeared to be impactful on signs and symptoms of radiation-associated damage with tissues such as salivary glands and skin (Table 1). In particular, compared to control patients, patients in Arms 1 and 2 had a lower incidence of dry mouth (none vs. 60%), dysphagia (none vs. 70%), salivary duct inflammation (none vs. 30%), candida infection (9.1% vs 40%), radiation associated skin injury (Arm 1 none, Arm 2 18.2%, control 70%) and weight loss (none vs. 50%) as examples. In this small proof of concept trial, RRx-001 infusion resulted in a reduction of multiple, biologically-related, side effects associated with a standard chemoradiation regimen used to the treatment of head and neck cancers. KEVLAR, a larger Phase 2b trial is planned to begin enrollment in Q4 of 2023 at about thirty sites in North America.

NLRP3 Inhibition Leads to Impaired Mucosal Fibroblast Function in Patients with Inflammatory Bowel Diseases.

Inflammatory bowel diseases (IBD) are characterized by mucosal inflammation and sequential fibrosis formation, but the exact role of the hyperactive NLRP3 inflammasome in these processes is unclear. Thus, we studied the expression and function of the NLRP3 inflammasome in the context of inflammation and fibrosis in IBD. We analysed intestinal NLRP3 expression in mucosal immune cells and fibroblasts from IBD patients and NLRP3-associated gene expression via single-cell RNA sequencing and microarray analyses. Furthermore, cytokine secretion of NLRP3 inhibitor treated blood and mucosal cells, as well as proliferation, collagen production, and cell death of NLRP3 inhibitor treated intestinal fibroblasts from IBD patients were studied. We found increased NLRP3 expression in the inflamed mucosa of IBD patients and NLRP3 inhibition led to reduced IL-1β and IL-18 production in blood cells and diminished the bioactive form of mucosal IL-1β. Single cell analysis identified overlapping expression patterns of NLRP3 and IL-1β in classically activated intestinal macrophages and we also detected NLRP3 expression in CD163+ macrophages. In addition, NLRP3 expression was also found in intestinal fibroblasts from IBD patients. Inhibition of NLRP3 led to reduced proliferation of intestinal fibroblasts, which was associated with a marked decrease in production of collagen type I and type VI in IBD patients. Moreover, NLRP3 inhibition in intestinal fibroblasts induced autophagy, a cellular process involved in collagen degradation. In the presented study, we demonstrate that inhibiting NLRP3 might pave the way for novel therapeutic approaches in IBD, especially to prevent the severe complication of intestinal fibrosis formation.

Xuanbai Chengqi Decoction alleviates acute lung injury by inhibiting NLRP3 inflammasome

Ethnopharmacological relevanceAcute lung injury/acute respiratory distress syndrome (ALI/ARDS) is a prevalent critical respiratory disorder caused mostly by infection and other factors. However, effective drug therapies are currently lacking. Xuanbai Chengqi Decoction (XCD), a traditional Chinese medicine (TCM) prescription, is commonly employed to treat lung diseases. It has been recommended by Chinese health authorities as one of the TCM prescriptions for COVID-19. Nonetheless, its underlying mechanism for the treatment of ALI has not been fully understood. Aim of the studyThe study aims to investigate the therapeutic effect of XCD on lipopolysaccharide (LPS) -induced ALI in mice and explore its anti-inflammatory mechanism involving pyroptosis. Materials and methodsUltra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) was employed to identify the active compounds of XCD, and quantitative analysis of the main compounds was conducted. Male C57BL/6J mice were given different doses of XCD (4.5 and 9.0 g/kg/day) or dexamethasone (5 mg/kg/day) by oral gavage for 5 consecutive days. Subsequently, ALI was induced by injecting LPS (20 mg/kg) intraperitoneally 2 h after the last administration, and serum and lung tissues were collected 8 h later. J774A.1 cells were pretreated with different doses of XCD (100, 200, 400 μg/ml) for 12 h, then incubated with LPS (1 μg/ml) for 4 h and ATP (1 mM) for 2 h to induce pyroptosis. Supernatant and cells were collected. Moreover, J774A.1 cells were transfected with an NLRP3 overexpression plasmid for 24 h, followed by subsequent experiments with XCD (400 μg/ml). Lung histopathological changes were evaluated using hematoxylin and eosin (HE) staining. To assess the efficacy of XCD on ALI/ARDS, the levels of inflammatory factors, chemokines, and proteins associated with NLRP3 inflammasome signaling pathway were evaluated. ResultsXCD was found to ameliorate lung inflammation injury in ALI mice, and reduce the protein expression of TNF-α, IL-1β, and IL-6 in both mouse serum and J774A.1 cell supernatant. Meanwhile, XCD significantly decreased the mRNA levels of IL-1β, pro-IL-1β, CXCL1, CXCL10, TNF-α, NLRP3, NF-κB P65, and the protein expression of NLRP3, Cleaved-Caspase1, and GSDMD-N in the lung and J774A.1 cells. These effects were consistent with the NLRP3 inhibitor MCC950. Furthermore, overexpression of NLRP3 reversed the anti-inflammatory effect of XCD. ConclusionThe therapeutic mechanism of XCD in ALI treatment may involve alleviating inflammatory responses in lung tissues by inhibiting the activation of the NLRP3 inflammasome-mediated pyroptosis in macrophages.

Role of NLRP3 in the exacerbation of ozone-induced allergic rhinitis

ObjectiveAllergic rhinitis (AR) is an immunoglobulin E (IgE)-mediated inflammatory disorder of the nasal mucosa, and the impact of ozone on AR is gaining increasing attention. Although NOD-like receptor thermal protein domain associated protein 3 (NLRP3) plays a crucial role in the pathogenesis of AR, its regulatory mechanisms in ozone-induced exacerbation remain unclear. Therefore, we explored the impact of ozone inhalation on inflammation in AR and investigated the regulatory mechanisms involving NLRP3. MethodsFifty female Sprague–Dawley rats were selected and divided into five groups: normal control (NC), normal with ozone exposure (NE), AR model, AR with ozone exposure (ARE), and ARE treated with the NLRP3 inhibitor MCC950 (ARE+MCC950). Behavioral changes were observed in the rats, and the expression of NLRP3, active-caspase 1, and GSDMD-N was detected by western blotting. The expression levels of interleukin (IL)− 4, IL-5, IL-13, IL-1β, and ovalbumin-specific IgE (OVA-sIgE) in nasal lavage fluid as well as IL-6 in the serum were measured by ELISA. The expression and distribution of NLRP3 and IL-1β in nasal mucosal tissue were detected by immunohistochemistry, and pathological changes and eosinophilic infiltration in nasal mucosal tissue were observed by hematoxylin and eosin (HE) staining. The effects of ozone exposure on inflammation in the nasal mucosal tissue of rats with AR and the relationship between NLRP3 and inflammation were analyzed. ResultsUpregulation of NLRP3 was observed in the AR rat model, and ozone further aggravated the expression of NLRP3 in the nasal mucosal tissue. Compared to the AR, NC, and NE groups, NLRP3 inflammasomes were activated in the ARE group, and the expression levels of related indexes active-caspase 1 and GSDMD-N were significantly increased; the expression levels of Th2 inflammatory factors IL-4, IL-5, IL-13, and OVA-sIgE were increased, and inflammatory factors such as IL-1β and IL-6 expression was also significantly increased. HE staining revealed that ozone aggravated damage to the nasal mucosal tissue in AR. Compared with the ARE group, the expression of NLRP3 inflammasomes was downregulated, sneezing and scratching symptoms were reduced, inflammatory indicators in nasal lavage fluid were decreased, and nasal mucosal tissue damage was alleviated in rats in the ARE+MCC950 group. ConclusionOzone exposure significantly increased the inflammatory response in an animal model of AR. MCC950 can selectively inhibit the expression of NLRP3, inhibit the activity of inflammasomes, and reduce nasal mucosal inflammation by regulating the NLRP3-caspase-1-IL-1β pathway.

Pancreatic Ductal Adenocarcinoma Cells Regulate NLRP3 Activation to Generate a Tolerogenic Microenvironment.

This study provides novel molecular insights on how PDAC cells exploit NLRP3 activation to suppress CD8 T-cell activation. From a translational perspective, we demonstrate that the combination of gemcitabine with the orally active NLRP3 inhibitor OLT1177 increases the efficacy of monotherapy.

HMSCs treatment attenuates murine herpesvirus-68 (MHV-68) pneumonia through altering innate immune response via ROS/NLRP3 signaling pathway

Immunocompromised individuals are particularly vulnerable to viral infections and reactivation, especially endogenous herpes viruses such as Epstein-Barr virus (EBV), a member of oncogenic gamma-herpesviruses, which are commonly linked to pneumonia and consequently significant morbidity and mortality. In the study of human and animal oncogenic gammaherpesviruses, the murine gamma-herpesviruses-68 (MHV-68) model has been applied, as it can induce pneumonia in immunocompromised mice. Mesenchymal stem cell (MSC) treatment has demonstrated therapeutic potential for pneumonia, as well as other forms of acute lung injury, in preclinical models. In this study, we aim to investigate the therapeutic efficacy and underlying mechanisms of human bone marrow-derived MSC (hMSC) on MHV-68-induced pneumonia. We found that intravenous administration of hMSCs significantly reduced lung damages, diminished inflammatory mediators and somehow inhibited MHV-68 replication. Furthermore, hMSCs treatment can regulate innate immune response and induce macrophage polarization from M1 to M2 phenotype, could significantly alter leukocyte infiltration and reduce pulmonary fibrosis. Our findings with co-culture system indicated that hMSCs effectively reduced the secretion of of inflammation-related factors and induced a shift in macrophage polarization, consistent with in vivo results. Further investigations revealed that hMSCs treatment suppressed the activation of macrophage ROS/NLRP3 signaling pathway in vivo and in vitro. Moreover, administration of MCC950, a selective NLRP3 inhibitor has been shown to effectively reduce ROS production and subsequently alleviate inflammation induced by MHV-68. Taken together, our work has shown that hMSCs can effectively protect mice from lethal MHV-68 pneumonia, which may throw new light on strategy for combating human EBV-associated pneumonia.

A multifunctional nanoaggregate‐based system for detection of rheumatoid arthritis via Optoacoustic/NIR‐II fluorescent imaging and therapy via inhibiting JAK‐STAT/NF‐κB/NLRP3 pathways

AbstractRheumatoid arthritis (RA) is a debilitating autoimmune disease that causes chronic pain and serious complications, presenting a significant challenge to treat. Promising approaches for treating RA involve signaling pathways modulation and targeted therapy. To this end, a multifunctional nanosystem, TPC‐U@HAT, has been designed for RA therapy, featuring multitargeting, dual‐stimuli response, and on‐demand drug release capabilities. TPC‐U@HAT is composed of a probe/prodrug TPC, a JAK1 kinase inhibitor upadacitinib, and the drug carrier HAT. TPC is composed of an aggregation‐induced emission (AIE)‐active NIR‐II chromophore TPY and an NF‐κB/NLRP3 inhibitor caffeic acid phenethyl ester (CAPE), connected via boronic ester bond which serves as the reactive‐oxygen‐species‐responsive linker. The carrier, HAT, is created by grafting bone‐targeting alendronate and hydrophobic tocopheryl succinate onto hyaluronic acid chains, which can encapsulate TPC and upadacitinib to form TPC‐U@HAT. Upon intravenous injection into mice, TPC‐U@HAT accumulates at inflamed lesions of RA through both active and passive targeting, and the overexpressed hyaluronidase and H2O2 therein cleave the hyaluronic acid polymer chains and boronate bonds, respectively. This generates an AIE‐active chromophore for detection and therapeutic evaluation of RA via both optoacoustic imaging and NIR‐II fluorescent imaging and concomitantly releases CAPE and upadacitinib to exert efficacious therapy by inhibiting NF‐κB/NLRP3 and JAK‐STAT pathways.

Discovery of NLRP3 inhibitors using machine learning: Identification of a hit compound to treat NLRP3 activation-driven diseases

NLRP3 is vital in developing many human diseases as one of the most critical inflammasomes. Developing related inhibitors has been instrumental in advancing the development of therapies for associated diseases. To date, there are no NLRP3 inhibitors on the market. This study identified a series of NLRP3 inhibitors using the self-developed machine learning model. Among them, CSC-6 was validated as the hit molecule with optimal activity and significantly inhibited IL-1β secreted by PMA-THP-1 cells (IC50 = 2.3 ± 0.38 μM). The results show that CSC-6 specifically binds NLRP3 and inhibits NLRP3 activation by blocking ASC oligomerization during NLRP3 assembly. In vivo experiments have demonstrated that CSC-6 effectively reduces the symptoms of NLRP3 overactivation-mediated sepsis and Gout in mouse models. Importantly, CSC-6 has lower cytotoxicity and exhibits better stability in human-derived liver microsomes, which is more favorable for the drug to maintain its efficacy in vivo for longer. The discovery of CSC-6 may contribute to the design and discovery of related NLRP3 inhibitors.

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<0.05), and DBP (day 1, Tet2 -/- : 108 ±3 mmHg vs. WT: 100±1 mmHg, P<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<0.005) and IL-18 (Tet2 -/- 1.56 vs. WT: 1.18, P<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.

43073 Pharmacokinetics, Safety and Pharmacodynamics of VTX2735, A Potent and Selective NLRP3 Inhibitor, In Healthy Adult Volunteers

43073 Pharmacokinetics, Safety and Pharmacodynamics of VTX2735, A Potent and Selective NLRP3 Inhibitor, In Healthy Adult Volunteers

Inflammasomes as a Prognostic Marker and Possible Therapeutic Target in Multiple Sclerosis: A Rapid Review of the Literature

Introduction: Inflammasomes are multiprotein complexes innate to the immune system that, upon activation, initiate a chain reaction culminating in the production of cytokines IL-1 and IL-18. Recent studies have suggested a connection between inflammasome activation and neurological diseases such as multiple sclerosis (MS). In this review, we aimed to evaluate the role of inflammasomes as potential therapeutic agents and prognostic markers of MS. Methods: Through a database search, 156 articles were identified. Of these, we selected articles focusing on observational and interventional studies that either directly measured the expression of inflammasomes or the levels of cytokines or interleukin as outcomes. After applying a snowball sampling strategy, this review ultimately included nine studies. Results: Our search yielded nine studies published between 2010 and 2022—9 observational studies included case-control and cohort designs. All studies comprised adult populations, 20–72 years of age. All studies incorporated a control group. We selected studies that utilized surrogate measures to evaluate outcomes such as inflammasome expression of NLRP3 or similar genes and assess cytokine levels such as IL-1β, IL-18, IL-23, and TNF. Discussion: Overall, the revised studies suggest a possible role for inflammasomes components, including ASC and caspase-1, which have been evaluated as potential prognostic markers in MS. Therapeutic strategies have focused on the inhibition of NLRP3, which is one of the most prominent and studied inflammasomes, by IFN-β.

Analysis of the potential pyroptosis mechanism in psoriasis and experimental validation of NLRP3 in vitro and in vivo

Pyroptosis provides new perspectives on the mechanisms underlying psoriasis and the development of new treatment strategies. Here, we aimed to identify pyroptosis-related genes (PRGs) involved in the pathogenesis and progression of psoriasis. Based on the inclusion/exclusion criteria, three gene datasets were downloaded from the Gene Expression Omnibus (GEO) database. Differential gene expression, weighted gene co-expression network analysis (WGCNA), and functional enrichment analyses were performed to identify candidate PRGs for psoriasis. Least absolute shrinkage and selection operator (LASSO) regression was used to identify hub genes, and receiver operating characteristic (ROC) curves were used to determine the clinical value of the hub genes. Imiquimod-inducedpsoriasis-like mice and lipopolysaccharide (LPS)-induced RAW 264.7 cells were employed to verify the pro-inflammatory factors that may drive changes in pyroptosis. In total, 159 skin samples were analysed, and a total of 21 common targets were obtained by crossing PRGs with all the differentially expressed genes (DEGs) in different disease states. 11 genes were identified via LASSO screening. Similarly, the last six PRGs biomarkers and the green module genes were screened. All hub genes with an area under the ROC curve > 0.5 were intersected, and NLRP3 was identified. NLRP3 expression was elevated in imiquimod-induced psoriatic lesions in mice and LPS-stimulated RAW 264.7 cells. The mice exhibited reduced psoriasis area and severity index scores, hyperproliferation, and inflammation after treatment with MCC950 (a specific inhibitor of NLRP3). MCC950 decreased IL-1β, IL-6, and TNF-α mRNA expression, and NLRP3 and p-p65 protein levels in LPS-stimulated RAW 264.7 cells. Our study indicates that NLRP3 may be a promising therapeutic target for the treatment of psoriasis.

Hederagenin inhibits high glucose-induced fibrosis in human renal cells by suppression of NLRP3 inflammasome activation through reducing cathepsin B expression.

Diabetic nephropathy is a major complication of diabetes mellitus and is related to dysfunction of renal cells. Hederagenin is a triterpenoid saponin from some Chinese herbs with anti-inflammatory and anti-diabetic activities. However, its role in diabetic nephropathy progression is still obscure. This study aimed to explore the effects of hederagenin on renal cell dysfunction in vitro. Human renal mesangial cells (HRMCs) and human renal proximal tubular epithelial cells (HRPTEpiCs) were cultured under high glucose (HG) conditions to mimic diabetic nephropathy-like injury. Cell proliferation was evaluated by CCK-8. mRNA and protein levels were determined by qRT-PCR and western blotting, respectively. The secretion levels of fibrosis-related biomarkers were analyzed by ELISA. Results showed that hederagenin reduced HG-induced proliferation increase in HRMCs and HRPTEpiCs. Hederagenin attenuated HG-induced increase in mRNA and protein expression of NLRP3, ASC, and IL-1β. Hederagenin also suppressed HG-induced increase in mRNA and secretion levels of FN, Col. IV, PAI-1, and TGF-β1. NLRP3 inhibitor MCC950 attenuated HG-induced fibrosis of renal cells, and its activator nigericin reversed the suppressive effect of hederagenin on HG-induced fibrosis. Bioinformatics analysis predicted cathepsin B (CTSB) as a target of hederagenin to modulate NOD-like receptor (NLR) pathway. Hederagenin decreased CTSB level, and CTSB overexpression reversed the suppressive effect of hederagenin on HG-induced NLRP3 inflammasome activation and fibrosis in HRMCs and HRPTEpiCs. In conclusion, hederagenin attenuates HG-induced fibrosis of renal cells by inhibiting NLRP3 inflammasome activation via reducing CTSB expression, indicating a therapeutic potential of hederagenin in diabetic nephropathy.