PANoptosis signaling enables broad immune response in psoriasis: From pathogenesis to new therapeutic strategies

Background

Accumulating evidence suggests that regulated cell death, such as pyroptosis, apoptosis, and necroptosis, is deeply involved in the pathogenesis of psoriasis. As a newly recognized form of systematic cell death, PANoptosis is involved in a variety of inflammatory disorders through amplifying inflammatory and immune cascades, but its role in psoriasis remains elusive.

Objectives

To reveal the role of PANoptosis in psoriasis for a potential therapeutic strategy.

Methods

Multitranscriptomic analysis and experimental validation were used to identify PANoptosis signaling in psoriasis. RNA-seq and scRNA-seq analyses were performed to establish a PANoptosis-mediated immune response in psoriasis, which revealed hub genes through WGCNA and predicted disulfiram as a potential drug. The effect and mechanism of disulfiram were verified in imiquimod (IMQ)-induced psoriasis.

Results

Here, we found a highlighted PANoptosis signature in psoriasis patients through multitranscriptomic analysis and experimental validation. Based on this, two distinct PANoptosis patterns (non/high) were identified, which were the options for clinical classification. The high-PANoptosis-related group had a higher response rate to immune cell infiltration (such as M1 macrophages and keratinocytes). Subsequently, WGCNA showed the hub genes (e.g., S100A12, CYCS, NOD2, STAT1, HSPA4, AIM2, MAPK7), which were significantly associated with clinical phenotype, PANoptosis signature, and identified immune response in psoriasis. Finally, we explored disulfiram (DSF) as a candidate drug for psoriasis through network pharmacology, which ameliorated IMQ-mediated psoriatic symptoms through antipyroptosis-mediated inflammation and enhanced apoptotic progression. By analyzing the specific ligand-receptor interaction pairs within and between cell lineages, we speculated that DSF might exert its effects by targeting keratinocytes directly or targeting M1 macrophages to downregulate the proliferation of keratinocytes.

Conclusions

PANoptosis with its mediated immune cell infiltration provides a roadmap for research on the pathogenesis and therapeutic strategies of psoriasis.

Ghrelin inhibits myocardial pyroptosis in diabetic cardiomyopathy by regulating ERS and NLRP3 inflammasome crosstalk through the PI3K/AKT pathway

AIMS

Endoplasmic reticulum stress(ERS) can induce inflammation mediated by NLRP3 inflammatory bodies and link inflammation with oxidative stress in myocardial tissue. Ghrelin is an endogenous growth hormone-releasing peptide that has been proven to have multiple effects, such as regulating energy metabolism and inhibiting inflammation. However, the role of ghrelin in myocardial injury in diabetic rats and the mechanism have not been reported.

RESULTS

We found that ghrelin could improve endoplasmic reticulum stress and inflammatory pyroptosis in the myocardial tissue of diabetic rats and reduce ERS and NLRP3 inflammasome crosstalk in H9C2 cardiomyocytes. Interestingly, ghrelin could activate the PI3K/AKT signalling pathway, playing a role in inhibiting endoplasmic reticulum stress and reducing the expression of pyroptosis-related proteins. However, these protective effects could be largely eliminated by LY294002.

CONCLUSIONS

In summary, we demonstrated that ghrelin inhibited myocardial pyroptosis in diabetic cardiomyopathy by regulating ERS and NLRP3 inflammasome crosstalk through the PI3K/AKT pathway. Our results provide new insights into the mechanism of diabetic myocardial injury induced by high glucose and high palmitic acid and ghrelin-mediated anti-inflammatory protection and provide potential therapeutic targets and strategies for diabetic cardiomyopathy.

Escherichia coli K88 activates NLRP3 inflammasome-mediated pyroptosis in vitro and in vivo

Pyroptosis induced by lipopolysaccharide (LPS) has an obvious impact on intestinal inflammation and immune regulation. Enterotoxigenic Escherichia coli (ETEC) K88 has been proved to induce inflammatory responses in several models, but whether E. coli K88 participates in the same process of pyroptotic cell death as LPS remains to be identified. We conducted a pilot experiment to confirm that E. coli K88, instead of Escherichia coli O157 and Salmonella typhimurium, promotes the secretion of interleukin-1 beta (IL-1β) and interleukin-18 (IL-18) in macrophages. Further experiments were carried out to dissect the molecular mechanism both in vitro and in vivo. The Enzyme-Linked Immunosorbent Assay (ELISA) results suggested that E. coli K88 treatment increased the expression of pro-inflammatory cytokines IL-18 and IL-1β in both C57BL/6 mice and the supernatant of J774A.1 cells. Intestinal morphology observations revealed that E. coli K88 treatment mainly induced inflammation in the colon. Real-time PCR and Western blot analysis showed that the mRNA and protein expressions of pyroptosis-related factors, such as NLRP3, ASC, and Caspase1, were significantly upregulated by E. coli K88 treatment. The RNA-seq results confirmed that the effect was associated with the activation of NLRP3, ASC, Caspase1, GSDMD, IL-18, and IL-1β, and might also be related to inflammatory bowel disease and the tumor necrosis factor pathway. The pyroptosis-activated effect of E. coli K88 was significantly blocked by NLRP3 siRNA. Our data suggested that E. coli K88 caused inflammation by triggering pyroptosis, which provides a theoretical basis for the prevention and treatment of ETEC in intestinal infection.

TLR2-dependent and independent pyroptosis in dTHP-1 cells induced by Actinomyces oris MG-1

In the immune system, the detection of pathogens through various mechanisms triggers immune responses. Several types of specific programmed cell deaths play a role in the inflammatory reaction. This study emphasizes the inflammatory response induced by Actinomycetes. Actinomyces spp. are resident bacteria in human oral plaque and often serve as a bridge for pathogenic bacteria, which lack affinity to the tooth surface, aiding their colonization of the plaque. We aim to investigate the potential role of Actinomyces oris in the early stages of oral diseases from a new perspective. Actinomyces oris MG-1 (A. oris) was chosen for this research. Differentiated THP-1 (dTHP-1) cells were transiently treated with A. oris to model the inflammatory reaction. Cell viability, as well as relative gene and protein expression levels of dTHP-1 cells, were assessed using CCK-8, quantitative real-time polymerase chain reaction (RT-qPCR), enzyme-linked immunosorbent assay (ELISA), and Western blot assay. The treatment decreased cell viability and increased the expression of inflammatory genes such as IL-1R1 and NLRP3. It was also observed to significantly enhance the release of IL-1β/IL-18 into the supernatant. Immunoblot analysis revealed a notable increase in the expression of N-gasdermin D persisting up to 24 h. Conversely, in models pre-treated with TLR2 inhibitors, N-gasdermin D was detectable only 12 h post-treatment and absent at 24 h. These results suggest that Actinomyces oris MG-1 induces pyroptosis in dTHP-1 cells via TLR2, but the process is not solely dependent on TLR2.

Microenvironment-responsive metal-phenolic network release platform with ROS scavenging, anti-pyroptosis, and ECM regeneration for intervertebral disc degeneration

Intervertebral disc degeneration (IVDD) can be caused by aging, injury, and genetic factors. The pathological changes associated with IVDD include the excessive accumulation of reactive oxygen species (ROS), cellular pyroptosis, and extracellular matrix (ECM) degradation. There are currently no approved specific molecular therapies for IVDD. In this study, we developed a multifunctional and microenvironment-responsive metal-phenolic network release platform, termed TMP@Alg-PBA/PVA, which could treat (IL-1β)-induced IVDD. The metal-phenolic network (TA-Mn-PVP, TMP) released from this platform targeted mitochondria to efficiently scavenge ROS and reduce ECM degradation. Pyroptosis was suppressed through the inhibition of the IL-17/ERK signaling pathway. These findings demonstrate the versatility of the platform. And in a rat model of IVDD, TMP@Alg-PBA/PVA exhibited excellent therapeutic effects by reducing the progression of the disease. TMP@Alg-PBA/PVA, therefore, presents clinical potential for the treatment of IVDD.

Mahuang Fuzi Xixin decoction alleviates allergic rhinitis by inhibiting NLRP3/Caspase-1/GSDMD-N-mediated pyroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Allergic rhinitis (AR) is a prevalent nasal inflammatory disorder, and pyroptosis plays a crucial role in aggravating AR. Current medications for AR treatment still have deficiencies, and finding new agents is of great interest. Mahuang Fuzi Xixin decoction (MFXD), an ancient Chinese medicine, is now commonly used to treat AR, which has anti-inflammatory and immunomodulatory effects, but its underlying mechanism is unknown.

AIM OF THIS STUDY

This study aims to evaluate the effects of MFXD on AR and explore its potential mechanisms in view of the regulatory effect on pyroptosis.

METHODS

MFXD, Mahuang, Fuzi, and Xixin water extracts were analyzed using ultra high performance liquid chromatography-Orbitrap-high-resolution accurate mass spectrometry. In in vivo study, the effects of MFXD on AR treatment were evaluated in an ovalbumin-induced mouse model. Mice were administered saline (control and model groups), MFXD (1.375, 2.75 g/kg), and dexamethasone (2.5 mg/kg) for 13 days. AR symptoms were evaluated by blinded observers. Immunoglobulin E (IgE) and histamine levels were measured using enzyme-linked immunosorbent assays. Expression of pyroptosis-related proteins (NLRP3, ASC, Caspase-1 p10/p20, GSDMD-N and IL-1β) in AR mouse nasal mucosa were estimated by immunohistochemistry. In in vivtro study, the effects of MFXD on pyroptosis were assessed in human nasal epithelial cells (HNEpCs) stimulated with lipopolysaccharide (LPS) and adenosine triphosphate (ATP), and incubated with MFXD (12.5, 25, and 50 μg/mL). Pyroptosis-related protein expression was measured by western blotting.

RESULTS

Thirty-three compounds in MFXD were identified, including ephedrine, pseudoephedrine, higenamine, aconine, aconitine, benzoylmesaconitine, benzoylhypaconine and hypaconitine. In the in vivo study, oral taken of MFXD/dexamethasone significantly ameliorated AR symptoms, reduced swelling of the nasal mucosa, and decreased the levels of IgE and histamine in AR mice serum. MFXD/dexamethasone attenuated histopathological changes and reduced the expression of pyroptosis-related proteins in nasal mucosa, indicating the inhibitory effect on nasal epithelial pyroptosis. In the in vitro study, MFXD (50 μg/mL) significantly alleviated cytotoxicity, protected cells from swelling and rupture, and downregulated the expression of pyroptosis-related proteins in LPS/ATP-induced HNEpCs.

CONCLUSION

MFXD suppressed nasal epithelial pyroptosis by inhibiting the NLRP3/Caspase-1/GSDMD-N signaling pathway, which alleviates AR. Our results offer valuable insights into potential AR therapies and provide evidence for the clinical utilization of MFXD to treat AR.

Self-adaptive pyroptosis-responsive nanoliposomes block pyroptosis in autoimmune inflammatory diseases

Nanoliposomes have a broad range of applications in the treatment of autoimmune inflammatory diseases because of their ability to considerably enhance drug transport. For their clinical application, nanoliposomes must be able to realize on-demand release of drugs at disease sites to maximize drug-delivery efficacy and minimize side effects. Therefore, responsive drug-release strategies for inflammation treatment have been explored; however, no specific design has been realized for a responsive drug-delivery system based on pyroptosis-related inflammation. Herein, we report a pioneering strategy for self-adaptive pyroptosis-responsive liposomes (R8-cardiolipin-containing nanoliposomes encapsulating dimethyl fumarate, RC-NL@DMF) that precisely release encapsulated anti-pyroptotic drugs into pyroptotic cells. The activated key pyroptotic protein, the N-terminal domain of gasdermin E, selectively integrates with the cardiolipin of liposomes, thus forming pores for controlled drug release, pyroptosis, and inflammation inhibition. Therefore, RC-NL@DMF exhibited effective therapeutic efficacies to alleviate autoimmune inflammatory damages in zymosan-induced arthritis mice and dextran sulfate sodium-induced inflammatory bowel disease mice. Our novel approach holds great promise for self-adaptive pyroptosis-responsive on-demand drug delivery, suppressing pyroptosis and treating autoimmune inflammatory diseases.

Mesenteric adipose tissue B lymphocytes promote intestinal injury in severe acute pancreatitis by mediating enteric pyroptosis

BACKGROUND

Visceral adipose tissue (VAT) has been linked to the severe acute pancreatitis (SAP) prognosis, although the underlying mechanism remains unclear. It has been reported that pyroptosis worsens SAP. The present study aimed to verify whether mesenteric adipose tissue (MAT, a component of VAT) can cause secondary intestinal injury through the pyroptotic pathway.

METHODS

Thirty-six male Sprague Dawley (SD) rats were divided into six different groups. Twelve rats were randomly divided into the SAP and control groups. We monitored the changes of MAT and B lymphocytes infiltration in MAT of SAP rats. Twelve SAP rats were injected with MAT B lymphocytes or phosphate buffer solution (PBS). The remaining twelve SAP rats were first injected with MAT B lymphocytes, and then with MCC950 (NLRP3 inhibitor) or PBS. We collected blood and tissue samples from pancreas, gut and MAT for analysis.

RESULTS

Compared to the control rats, the SAP group showed inflammation in MAT, including higher expression of tumor necrosis factor (TNF-α) and interleukin-6 (IL-6), lower expression of IL-10, and histological changes. Flow cytometry analysis revealed B lymphocytes infiltration in MAT but not T lymphocytes and macrophages. The SAP rats also exhibited intestinal injury, characterized by lower expression of zonula occludens-1 (ZO-1) and occludin, higher levels of lipopolysaccharide and diamine oxidase, and pathological changes. The expression of NLRP3 and n-GSDMD, which are responsible for pyroptosis, was increased in the intestine of SAP rats. The injection of MAT B lymphocytes into SAP rats exacerbated the inflammation in MAT. The upregulation of pyroptosis reduced tight junction in the intestine, which contributed to the SAP progression, including higher inflammatory indicators and worse histological changes. The administration of MCC950 to SAP + MAT B rats downregulated pyroptosis, which subsequently improved the intestinal barrier and ameliorated inflammatory response of SAP.

CONCLUSIONS

In SAP, MAT B lymphocytes aggravated local inflammation, and promoted the injury to the intestine through the enteric pyroptotic pathway.

Canonical pathways for validating steroid-associated osteonecrosis in mice

The present study aimed to establish and evaluate a preclinical model of steroid-associated osteonecrosis (SAON) in mice. Sixteen 24-week-old male C57BL/6 mice were used to establish SAON by two intraperitoneal injections of lipopolysaccharide (LPS), followed by three subcutaneous injections of methylprednisolone (MPS). Each injection was conducted on working day, with an interval of 24 h. Six cycles of injections were conducted. Additional twelve mice (age- and gender-matched) were used as normal controls. At 2 and 6 weeks after completing induction, bilateral femora and bilateral tibiae were collected for histological examination, micro-CT scanning, and bulk RNA sequencing. All mice were alive until sacrificed at the indicated time points. The typical SAON lesion was identified by histological evaluation at week 2 and week 6 with increased lacunae and TUNEL+ osteocytes. Micro-CT showed significant bone degeneration at week 6 in SAON model. Histology and histomorphometry showed significantly lower Runx2+ area, mineralizing surface (MS/BS), mineral apposition rate (MAR), bone formation rate (BFR/BS), type H vessels, Ki67+ (proliferating) cells, and higher marrow fat fraction, osteoclast number and TNFα+ areas in SAON group. Bulk RNA-seq revealed changed canonical signaling pathways regulating cell cycle, angiogenesis, osteogenesis, and osteoclastogenesis in the SAON group. The present study successfully established SAON in mice with a combination treatment of LPS and MPS, which could be considered a reliable and reproducible animal model to study the pathophysiology and molecular mechanism of early-stage SAON and to develop potential therapeutic approaches for the prevention and treatment of SAON.

Intestinal microbiota via NLRP3 inflammasome dependent neuronal pyroptosis mediates anxiety-like behaviour in mice exposed to 3.5 GHz radiofrequency radiation

The rapid development of 5G communication technology has increased public concern about the potential adverse effects on human health. Till now, the impacts of radiofrequency radiation (RFR) from 5G communication on the central nervous system and gut-brain axis are still unclear. Therefore, we investigated the effects of 3.5 GHz (a frequency commonly used in 5G communication) RFR on neurobehavior, gut microbiota, and gut-brain axis metabolites in mice. The results showed that exposure to 3.5 GHz RFR at 50 W/m2 for 1 h over 35 d induced anxiety-like behaviour in mice, accompanied by NLRP3-dependent neuronal pyroptosis in CA3 region of the dorsal hippocampus. In addition, the microbial composition was widely divergent between the sham and RFR groups. 3.5 GHz RFR also caused changes in metabolites of feces, serum, and brain. The differential metabolites were mainly enriched in glycerophospholipid metabolism, tryptophan metabolism, and arginine biosynthesis. Further correlation analysis showed that gut microbiota dysbiosis was associated with differential metabolites. Based on the above results, we speculate that dysfunctional intestinal flora and metabolites may be involved in RFR-induced anxiety-like behaviour in mice through neuronal pyroptosis in the brain. The findings provide novel insights into the mechanism of 5G RFR-induced neurotoxicity.

Effect of M0 macrophage-derived exosome miR-181d-5p targeting BCL-2 to regulate NLRP3/caspase-1/GSDMD pathway on human renal mesangial cells pyroptosis

BACKGROUND

Lupus nephritis (LN) is a type of autoimmune disease that impacts the kidneys. Exosomes are valuable for in-depth studies of the pathogenesis of LN. This study aimed to explore miR-181d-5p expression levels in M0 macrophage-derived exosomes and their role in human renal mesangial cells (HRMC) pyroptosis through binding to BCL-2.

METHODS

Peripheral blood mononuclear cells (PBMCs) were collected from patients with lupus nephritis (LN) and healthy subjects. Monocytes isolated from these samples were induced into M0 macrophages using recombinant human granulocyte colony-stimulating factor (rhG-CSF). In a parallel process, THP-1 cells were induced into M0 macrophages using Phorbol Myristate Acetate (PMA). LPS- and ATP-stimulated HRMC were used to construct a cell pyroptosis model. We then introduced different miR-181d-5p mimic fragments into the M0 macrophages derived from the THP-1 cells. Subsequently, exosomes from these macrophages were co-cultured with HRMC. To evaluate the impact on HRMC, we conducted proliferation and apoptosis assessments using CellCountingKit-8assay and flow cytometry. The effect of exosomal miR-181d-5p on HRMC pyroptosis was assessed using western blot. The miR-181d-5p and BCL-2 targeting relationship was detected using real-time fluorescence quantitative PCR. IL-6, IL-1β, and TNF-α levels in cell supernatants were detected using ELISA kits.

RESULTS

In this study, we observed an increase in miR-181d-5p levels within exosomes secreted from M0 macrophages obtained by induction of monocytes from LN patients. It was found that miR-181d-5p can target binding to BCL-2. Exosomes with elevated levels of miR-181d-5p contributed to a significant increase in miR-181d-5p within HRMC, facilitating its proliferation and inhibiting apoptosis. Furthermore, exosomes expressing high levels of miR-181d-5p were observed to promote an inflammatory response and pyroptosis in HRMC. Notably, these effects were reversed when the levels of miR-181d-5p in the exosomes were reduced.

CONCLUSION

Inhibition of miR-181d-5p, derived from M0 macrophage exosomes, effectively suppresses inflammation and pyroptosis in HRMC. This discovery indicates that miR-181d-5p holds the potential as a valuable target in the development of treatments for Lupus Nephritis (LN).

Free total rhubarb anthraquinones protect intestinal mucosal barrier of SAP rats via inhibiting the NLRP3/caspase-1/GSDMD pyroptotic pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Rhubarb is the peeled and dried roots of Rheum palmatum L. and Rheum tanguticum Maxim. ex Balf. or Rheum officinale Baill. Free total rhubarb anthraquinones (FTRAs) were isolated and extracted from rhubarb. Previous studies have revealed that the early administration of FTRAs protects the intestinal mucosal barrier in rats with severe acute pancreatitis (SAP), the mechanism of which is not yet clear. However, we observed an enhanced expression of intestinal pyroptotic factors in rats treated with SAP, which may be related to the mechanism of intestinal barrier protection by FTRAs.

AIM OF THE STUDY

The main objective of this study was to investigate the mechanism by which FTRAs protect the intestinal mucosal barrier in SAP rats, focusing on the classical pyroptosis pathway.

MATERIALS AND METHODS

SAP was induced in rats through retrograde injection of sodium taurocholate via the pancreaticobiliary duct. Subsequently, FTRAs (22.5, 45, and 90 mg/kg), rhubarb (900 mg/kg, positive control), and saline (control) were administered at 0 h (immediately), 12 h, and 24 h post-surgery. Pancreatic and intestinal tissue injury, positive PI staining rate, and expression levels of various factors in intestinal tissues were compared across different groups. These factors include diamine oxidase (DAO), lactate dehydrogenase (LDH), high mobility group box chromosomal protein 1(HMGB1) and pro-inflammatory factors in intestinal and serum, pyroptosis-associated factors, toll-like receptor 4 (TLR-4), nuclear factor kappa-B (NF-kB), apoptosis-associated speck-like protein (ASC), NOD-like receptor protein 3 (NLRP3), cysteine protease-1 (caspase-1) and Gasdermin (GSDMD).

RESULTS

The findings indicated that FTRAs protected the damaged intestine and pancreas and restored the expression of intestinal epithelial junction proteins in SAP rats. Additionally, it reduced intestinal and serum levels of DAO, interleukin 1, interleukin 18, HMGB1, and LDH, attenuated intestinal Positive PI staining rate, and significantly decreased the expressions of TLR-4, NF-kB, ASC, NLRP3, caspase-1 and GSDMD in SAP rats.

CONCLUSIONS

The results suggest that FTRAs inhibited pyroptosis through down-regulation of the NLRP3-Caspase-1-GSDMD and TLR-4- NF-kB signaling pathways of intestinal tissues., thereby protecting the intestinal barrier of SAP rats.

Transcriptomics confirms IRF1 as a key regulator of pyroptosis in diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is a retinal microvascular complication caused by hyperglycemia, which can lead to visual impairment or blindness. Pyroptosis is a type of inflammation-related programmed cell death, activated by caspase-1, resulting in the maturation of IL-1β and IL-18 and the rupture of the cell membrane. RNA sequencing (RNA-seq) is a high-throughput sequencing technique that reveals the presence and quantity of RNA in the genome at a specific time point, i.e., the transcriptome. RNA-seq can analyze gene expression levels, splicing variants, mutations, fusions, editing and other post-transcriptional modifications, as well as gene expression differences between different samples or conditions. It has been widely used in biological and medical research, clinical diagnosis and new drug development. This study aimed to establish an in vitro model of diabetic retinopathy by culturing human retinal endothelial cells (HREC) with high glucose (30 mmol/L), and to detect their transcriptome expression by RNA-seq, screen for key genes related to pyroptosis, and validate the sequencing results by subsequent experiments.

METHODS

We used RNA-seq to detect the transcriptome expression differences between HREC cells cultured with high glucose and control group, and identified differentially expressed genes by GO/KEGG analysis. We constructed a PPI network and determined the key genes by Cytoscape software and CytoHubba plugin. We validated the expression of related factors by Western Blot, qPCR and ELISA.

RESULTS

We performed GO and KEGG analysis on the RNA-seq data and found differentially expressed genes. We used Cytoscape and CytoHubba plugin to screen out IRF1 as the key gene, and then detected the expression of IRF1 in HREC under high glucose and control group by Western Blot and qPCR. We found that the expression of Caspase-1, GSDMD and IL-1β proteins in HREC under high glucose increased, while the expression of these proteins decreased after the inhibition of IRF1 by siRNA. ELISA showed that the secretion of IL-1β in HREC under high glucose increased, while the inhibition of IRF1 reduced the secretion of IL-1β. These results indicate that IRF1 plays an important role in DR, and provides a new target and strategy for the prevention and treatment of this disease.

Di (2-ethylhexyl) phthalate and polystyrene microplastics co-exposure caused oxidative stress to activate NF-κB/NLRP3 pathway aggravated pyroptosis and inflammation in mouse kidney

Polystyrene microplastic (PS-MPs) contamination has become a worldwide hotspot of concern, and its entry into organisms can cause oxidative stress resulting in multi-organ damage. The plasticizer di (2-ethylhexyl) phthalate (DEHP) is a common endocrine disruptor, these two environmental toxins often occur together, but their combined toxicity to the kidney and its mechanism of toxicity are unknown. Therefore, in this study, we established PS-MPS and/or DEHP-exposed mouse models. The results showed that alone exposure to both PS-MPs and DEHP caused inflammatory cell infiltration, cell membrane rupture, and content spillage in kidney tissues. There were also down-regulation of antioxidant enzyme levels, increased ROS content, activated of the NF-κB pathway, stimulated the levels of heat shock proteins (HSPs), pyroptosis, and inflammatory associated factors. Notably, the co-exposure group showed greater toxicity to kidney tissues, the cellular assay further validated these results. The introduction of the antioxidant n-acetylcysteine (NAC) and the NLRP3 inhibitor (MCC950) could mitigate the changes in the above measures. In summary, co-exposure of PS-MPs and DEHP induced oxidative stress that activated the NF-κB/NLRP3 pathway and aggravated kidney pyroptosis and inflammation, as well as that HSPs are also involved in this pathologic injury process. This study not only enriched the nephrotoxicity of plasticizers and microplastics, but also provided new insights into the toxicity mechanisms of multicomponent co-pollution in environmental.

Fluoride induces pyroptosis via IL-17A-mediated caspase-1/11-dependent pathways and Bifidobacterium intervention in testis

Fluoride, a ubiquitous environmental pollutant, poses a significant public health threat. Our previous study revealed a correlation between fluoride-induced testicular pyroptosis and male reproductive dysfunction. However, the underlying mechanism remains unclear. Wild-type and interleukin 17A knockout mice were exposed to sodium fluoride (100 mg/L) in deionized drinking water for 18 weeks. Bifidobacterium intervention (1 × 109 CFU/mL, 0.2 mL/day, administered via gavage) commenced in the 10th week. Sperm quality, testicular morphology, key pyroptosis markers, spermatogenesis key genes, IL-17A signaling pathway, and pyroptosis pathway related genes were determined. The results showed that fluoride reduced sperm quality, damaged testicular morphology, affected spermatogenesis, elevated IL-17A levels, and induced testicular pyroptosis. Bifidobacterium intervention alleviated adverse reproductive outcomes. Fluoride-activated testicular pyroptosis through both typical and atypical pathways, with IL-17A involvement. Bifidobacterium supplementation attenuated pyroptosis by downregulating IL-17A, inhibiting NLRP3 and PYRIN-mediated caspase-1 and caspase-11 dependent pathways in testis, thereby alleviating fluoride-induced male reproductive damage. In summary, this study uncovers the mechanism underlying fluorine-induced testicular pyroptosis and illustrates the novel protecting feature of Bifidobacterium against fluoride-induced harm to male reproduction, along with its potential regulatory mechanism. These results provide fresh perspectives on treating male reproductive dysfunction resulting from fluoride or other environmental toxins.

Pyroptosis in myocardial ischemia/reperfusion and its therapeutic implications

Ischemic heart disease, a prevalent cardiovascular disease with global significance, is associated with substantial morbidity. Timely and successful reperfusion is crucial for reducing infarct size and enhancing clinical outcomes. However, reperfusion may induce additional myocardium injury, manifesting as myocardial ischemia/reperfusion (MI/R) injury. Pyroptosis is a regulated cell death pathway, the signaling pathway of which is activated during MI/R injury. In this process, the inflammasomes are triggered, initiating the cleavage of gasdermin proteins and pro-interleukins, which results in the formation of membrane pores and the maturation and secretion of inflammatory cytokines. Numerous preclinical evidence underscores the pivotal role of pyroptosis in MI/R injury. Inhibiting pyroptosis is cardioprotective against MI/R injury. Although certain agents exhibiting promise in preclinical studies for attenuating MI/R injury through inhibiting pyroptosis have been identified, the suitability of these compounds for clinical trials remains untested. This review comprehensively summarizes the recent developments in this field, with a specific emphasis on the impact of pyroptosis on MI/R injury. Deciphering these findings not only sheds light on new disease mechanisms but also paves the way for innovative treatments. And then the exploration of the latest advances in compounds that inhibit pyroptosis in MI/R is discussed, which aims to provide insights into potential therapeutic strategies and identify avenues for future research in the pursuit of effective clinical interventions.

Glycosides of Buyang Huanwu decoction inhibits inflammation associated with cerebral ischemia-reperfusion via the PINK1/Parkin mitophagy pathway

ETHNOPHARMACOLOGICAL RELEVANCE

A classic stroke formula is Buyang Huanwu Decoction (BYHWD), Glycosides are the pharmacological components found in BYHWD, which are utilized for the prevention and management of cerebral ischemia-reperfusion (CIR), as demonstrated in a previous study. Its neuroprotective properties are closely related to its ability to modulate inflammation, but its mechanism is as yet unclear.

AIM OF THE STUDY

A research was undertaken to investigate the impact of glycosides on the inflammation of CIR through the PTEN-induced putative kinase-1 (PINK1)/Parkin mitophagy pathway.

MATERIALS AND METHODS

Analyzing glycosides containing serum components was performed with ultra-performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF-MS). Glycosides were applied to rat of Middle cerebral artery occlusion/reperfusion (MCAO/R) model and primary neural cell of Oxygen glucose deprivation/reperfusion (OGD/R) model. The neuroprotective effect and the regulation of mitophagy of glycosides were evaluated through neural damage and PINK1/Parkin mitophagy activation. Moreover, the assessment of the relationship between glycosides regulation of mitophagy and its anti-inflammatory effects subsequent to mitophagy blockade was conducted by examining neural damage, PINK1/Parkin mitophagy activation, and levels of pyroptosis.

RESULTS

(1) It was observed that the administration of glycosides resulted in a decrease in neurological function scores, a reduction in cerebral infarction volume, an increase in mitochondrial autophagosome, and the maintenance of a high expression status of light chain 3 (LC3) II/LC3Ⅰ protein. Additionally, there was a significant inhibition of p62 protein expression and an enhancement of PINK1 and Parkin protein expression. Furthermore, it was found that the effect of glycosides at a dosage of 0.128 g · kg-1 was significantly superior to that of glycosides at a dosage of 0.064 g · kg-1. Notably, the neuroprotective effect and inhibition of pyroptosis protein of glycosides at a dosage of 0.128 g · kg-1 were attenuated when mitochondrial autophagy was blocked. (2) Glycosides repaired cellular morphological damage, enhanced cell survival, and reduced Lactate dehydrogenase (LDH) leakage, with glycosides (2.36 μg·mL-1 and 4.72 μg·mL-1) neuronal protection being the strongest. Glycosides (4.72 μg·mL-1) maintained LC3II/LC3Ⅰ protein high expression state, inhibited p62 protein expression, and promoted PINK1 and Parkin protein expression, which was stronger than glycosides (2.36 μg·mL-1). The blockade of mitophagy resulted in a reduction of neuroprotection and inhibition of pyroptosis protein exerted by glycosides.

CONCLUSION

Glycosides demonstrate the ability to hinder inflammation through the activation of the PINK1/Parkin mitophagy pathway, thereby leading to subsequent neuroprotective effects on CIR.

MG53 protects against Coxsackievirus B3-induced acute viral myocarditis in mice by inhibiting NLRP3 inflammasome-mediated pyroptosis via the NF-κB signaling pathway

Pyroptosis, a novel programmed cell death mediated by NOD-like receptor protein 3 (NLRP3) inflammasome, is a critical pathogenic process in acute viral myocarditis (AVMC). Mitsugumin 53 (MG53) is predominantly expressed in myocardial tissues and has been reported to exert cardioprotective effects through multiple pathways. Herein, we aimed to investigate the biological function of MG53 in AVMC and its underlying regulatory mechanism in pyroptosis. BALB/c mice and HL-1 cells were infected with Coxsackievirus B3 (CVB3) to establish animal and cellular models of AVMC. As inflammation progressed in the myocardium, we found a progressive decrease in myocardial MG53 expression, accompanied by a significant enhancement of cardiomyocyte pyroptosis. MG53 overexpression significantly alleviated myocardial inflammation, apoptosis, fibrosis, and mitochondrial damage, thereby improving cardiac dysfunction in AVMC mice. Moreover, MG53 overexpression inhibited NLRP3 inflammasome-mediated pyroptosis, reduced pro-inflammatory cytokines (IL-1β/18) release, and suppressed NF-κB signaling pathway activation both in vivo and in vitro. Conversely, MG53 knockdown reduced cell viability, facilitated cell pyroptosis, and increased pro-inflammatory cytokines release in CVB3-infected HL-1 cells by promoting NF-κB activation. These effects were partially reversed by applying the NF-κB inhibitor BAY 11-7082. In conclusion, our results suggest that MG53 acts as a negative regulator of NLRP3 inflammasome-mediated pyroptosis in CVB3-induced AVMC, partially by inhibiting the NF-κB signaling pathway. MG53 is a promising candidate for clinical applications in AVMC treatment.

Platelet-rich plasma-derived extracellular vesicles inhibit NF-κB/NLRP3 pathway-mediated pyroptosis in intervertebral disc degeneration via the MALAT1/microRNA-217/SIRT1 axis

BACKGROUND

Intervertebral disc degeneration (IDD) is a main contributor to lower back pain, and compression stress-induced apoptosis of nucleus pulposus (NP) cells and extracellular matrix (ECM) degradation has been implicated in the IDD progression. The functions of platelet-rich plasma (PRP)-derived extracellular vesicles (PRP-EVs) in regulating these biological processes remain unclear in IDD. Here, we aimed to investigate the key role of long noncoding RNA (lncRNA) MALAT1 incorporated in PRP-EVs in IDD.

METHODS

Tert-butyl hydroperoxide (TBHP)-induced damage in NP cells was treated with PRP-EVs extracted from healthy volunteers, followed by MTT, EdU, TUNEL, and Western blot assays. IDD mice were also treated with PRP-EVs. Histomorphological and pathological changes were evaluated. The pyroptosis of cells and the degradation of ECM were detected by ELISA and immunohistochemistry. We screened the differentially expressed lncRNAs in NP cells after PRP-EVs treatment by microarray analysis. The downstream targets of MALAT1 in NP cells were predicted and validated by rescue experiments.

FINDINGS

TBHP induction reduced cell proliferation and exacerbated pyroptosis and ECM degradation, and PRP-EVs inhibited TBHP-induced cell damage. PRP-EVs-treated mice with IDD had reduced Thompson scores, increased NP tissue content, and restored ECM. PRP-EVs upregulated MALAT1 expression in vivo and in vitro, whereas MALAT1 downregulation exacerbated NP cell pyroptosis and ECM degradation. MALAT1 upregulated SIRT1 expression by downregulating microRNA (miR)-217 in NP cells. SIRT1 blocked the NF-κB/NLRP3 pathway-mediated pyroptosis, thereby alleviating IDD.

INTERPRETATION

PRP-EVs deliver MALAT1 to regulate miR-217/SIRT1, thereby controlling NP cell pyroptosis in IDD.

Hyperactivation of succinate dehydrogenase promotes pyroptosis of macrophage via ROS-induced GSDMD oligomerization in acute liver failure

Acute liver failure (ALF) is a life-threatening disease with high mortality. Given excessive inflammation is one of the major pathogenesis of ALF, candidates targeting inflammation could be beneficial in the condition. Now the effect of hyperactivated succinate dehydrogenase (SDH) on promoting inflammation in lipopolysaccharide (LPS)-treated macrophages has been studied. However, its role and mechanism in ALF is not well understood. Here intraperitoneal injection of D-galactosamine and LPS was conducted in male C57BL/6 J mice to induce the ALF model. Dimethyl malonate (DMM), which inhibited SDH activity, was injected intraperitoneally 30 min before ALF induction. Macrophage pyroptosis was induced by LPS plus adenosine triphosphate (ATP). Pyroptosis-related molecules and proteins including GSDMD oligomer were examined by ELISA and western blot techniques, respectively. ROS production was assessed by fluorescence staining. The study demonstrated SDH activity was increased in liver macrophages from ALF mice. Importantly, DMM administration inhibited ROS, IL-1β, and pyroptosis-associated proteins levels (NLRP3, cleaved caspase-1, GSDMD-N, and GSDMD oligomers) both in the ALF model and in macrophages stimulated with LPS plus ATP. In vitro, ROS promoted pyroptosis by facilitating GSDMD oligomerization. Additionally, when ROS levels were increased through the addition of H2O2 to the DMM group, the levels of GSDMD oligomers were reverted. In conclusion, SDH hyperactivation promotes macrophage pyroptosis by ROS-mediated GSDMD oligomerization, suggesting that targeting this pathway holds promise as a strategy for treating ALF and other inflammatory diseases.

Maternal exposure to ZIF-8 derails placental function by inducing trophoblast pyroptosis through neutrophils activation in mice

Adverse environmental factors during maternal gestation pose a threat to pregnancy. Environmental factors, particularly nanoparticles, can impact pregnancy by causing damage to the placenta. Compared to early gestation, foetuses in late gestation are more robustly developed and at lower risk of adverse effects from environmental factors. Delivery systems for targeted therapy during pregnancy is predominantly focused on their application in late gestation. Zeolitic imidazolate framework-8 (ZIF-8) holds great potential for targeted drug therapy. To evaluate the value of ZIF-8 in targeted treatment of disorders associated with late gestation, it is crucial to investigate the biological effects of ZIF-8 exposure during late gestation. Here, a mouse model exposed to ZIF-8 particles at different doses (5, 10, and 15 mg/kg) during late gestation was constructed. We found that ZIF-8 particles were deposited in the uterus of pregnant mice. ZIF-8 could trigger placental neutrophil aggregation and induce inflammation, which led to trophoblast pyroptosis and impair placental function, adversely affecting the foetus. Neutrophil depletion alleviated placental and foetal damage induced by ZIF-8. This study provides a novel mechanistic view of the reproductive toxicity induced by ZIF-8 and may offer clues to reduce the latent harm of adverse environmental factors to pregnancy.

Curcumin attenuates aflatoxin B1-induced ileum injury in ducks by inhibiting NLRP3 inflammasome and regulating TLR4/NF-κB signaling pathway

Aflatoxin B1 (AFB1) is a widespread toxic contamination in feed for animals. The primary active component of turmeric, curcumin (Cur), is an antioxidant and an anti-inflammatory. However, it is yet unknown how AFB1 affects the intestinal epithelial barrier and whether Cur acts as a protective mechanism when exposed to AFB1. Here, we explored the mechanism of AFB1-induced intestinal injury from intestinal epithelial barrier, inflammation, pyroptosis, and intestinal flora, and evaluated the protective role of Cur. We found that AFB1 caused weight loss and intestinal morphological damage that is mainly characterized by shortened intestinal villi, deepened crypts, and damaged intestinal epithelium. Exposure to AFB1 decreased the expression of Claudin-1, MUC2, ZO-1, and Occludin and increased the expression of pyroptosis-related factors (NLRP3, GSDMD, Caspase-1, IL-1β, and IL-18) and inflammation-related factors (TLR4, NF-κB, IκB, IFN-γ, and TNF-α). Furthermore, ileal gut microbiota was altered, and simultaneously, the Lactobacillus abundance was decreased. The gut microbiota interacts with a wide range of physiologic functions and disease development in the host through its metabolites, and disturbances in gut microbial metabolism can cause functional impairment of the ileum. Meanwhile, Cur can ameliorate histological ileum injuries and intestinal flora disturbance caused by AFB1. We found that Cur reversed the effects of AFB1 through modulating both NLRP3 inflammasome and the TLR4/NF-κB signaling pathway. In conclusion, AFB1 can induce inflammatory damage and pyroptosis in duck ileum, while Cur has obviously protective effects on all the above damages.

From growth promotion to intestinal inflammation alleviation: Unraveling the potential role of Lactobacillus rhamnosus GCC-3 in juvenile grass carp (Ctenopharyngodon idella)

Lactobacillus rhamnosus is a probiotic, which not only promotes the growth of animals, but also has anti-inflammatory effects. However, the mechanism by which Lactobacillus rhamnosus regulates intestinal immunity is not well comprehended. Hence, the study aimed to research how Lactobacillus rhamnosus affects the intestinal immunity using juvenile grass carp (Ctenopharyngodon idella) as a model. We selected 1800 juvenile grass carp for testing. They were divided into six treatments and fed with six gradients of Lactobacillus rhamnosus GCC-3 (0.0, 0.5, 1.0, 1.5, 2.0, 2.5 g/kg) for 70 days. Enteritis was subsequently induced with dextroside sodium sulfate. Results indicated that dietary Lactobacillus rhamnosus GCC-3 addition improved growth performance. Meanwhile, appropriate levels of Lactobacillus rhamnosus GCC-3 alleviated excessive inflammatory response by down-regulating the expression of TLR4 and NOD receptors, up-regulating the expression of TOR, and then down-regulating the expression of NF-κB. Additionally, appropriate Lactobacillus rhamnosus GCC-3 improved intestinal immunity by reducing pyroptosis triggered by NLRP3 inflammasome and mediated by GSDME. Furthermore, 16 S rRNA sequencing showing appropriate levels of Lactobacillus rhamnosus GCC-3 increased Lactobacillus and Bifidobacterium abundance and decreased Aeromonas abundance. These results suggest that Lactobacillus rhamnosus GCC-3 can alleviate intestinal inflammation through down-regulating NF-κB and up-regulating TOR signaling pathways, as well as by inhibiting pyroptosis.

Lipopolysaccharide-induced intestinal inflammation on AIM2-mediated pyroptosis in the brain of rats with cerebral small vessel disease

Cerebral small vessel disease (CSVD) is a cerebral vascular disease with insidious onset and poor clinical treatment effect, which is related to neuroinflammation. This study investigated whether lipopolysaccharide-induced intestinal inflammation enhanced the level of pyroptosis in the brain of rats with CSVD. The bilateral carotid artery occlusion (BCAO) model was selected as the object of study. Firstly, behavioral tests and Hematoxylin-eosin staining (HE staining) were performed to determine whether the model was successful, and then the AIM2 inflammasome and pyroptosis indexes (AIM2, ASC, Caspase-1, IL-1β, GSDMD, N-GSDMD) in the brain were detected by Western blotting and Immunohistochemistry (IHC). Finally, a single intraperitoneal injection of lipopolysaccharide (LPS) was used to induce intestinal inflammation in rats, the expression of GSDMD and N-GSDMD in the brain was analyzed by Western blotting and to see if pyroptosis caused by intestinal inflammation can be inhibited by Disulfiram, an inhibitor of pyroptosis. The results showed that the inflammatory response and pyroptosis mediated by the AIM2 inflammasome in BCAO rats were present in both brain and intestine. The expression of N-GSDMD, a key marker of pyroptosis, in the brain was significantly increased and inhibited by Disulfiram after LPS-induced enhancement of intestinal inflammation. This study shows that AIM2-mediated inflammasome activation and pyroptosis exist in both brain and intestine in the rat model of CSVD. The enhancement of intestinal inflammation will increase the level of pyroptosis in the brain. In the future, targeted regulation of the AIM2 inflammasome may become a new strategy for the clinical treatment of CSVD.

Role of Selenoprotein W in participating in the progression of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease worldwide. Numerous evidence has demonstrated that metabolic reprogramming serves as a hallmark associated with an elevated risk of NAFLD progression. Selenoprotein W (SelW) is an extensively expressed hepatic selenoprotein that plays a crucial role in antioxidant function. Here, we first demonstrated that SelW is a significantly distinct factor in the liver tissue of NAFLD patients through the Gene Expression Omnibus (GEO) database. Additionally, loss of SelW alleviated hepatic steatosis induced by a high-fat diet (HFD), and was accompanied by the regulation of metabolic and inflammatory pathways as verified by transcriptomic analysis. Moreover, co-immunoprecipitation (CO-IP), liquid chromatography-tandem mass spectrometry (LC-MS), laser scanning confocal microscopy (LSCM) and molecular docking analysis were subsequently implemented to identify Pyruvate Kinase M2 (PKM2) as a potential interacting protein of SelW. Meanwhile, SelW modulated PKM2 translocation into the nucleus to trigger transactivation of the HIF-1α, in further mediating mitochondrial apoptosis, eventually resulting in mitochondrial damage, ROS excessive production and mtDNA leakage. Additionally, mito-ROS accumulation induced the activation of the NLRP3 inflammasome-mediated pyroptosis, thereby facilitating extracellular leakage of mtDNA. The escaped mtDNA then evokes the cGAS-STING signaling pathway in macrophage, thus inducing a shift in macrophage phenotype. Together, our results suggest SelW promotes hepatocyte apoptosis and pyroptosis by regulating metabolic reprogramming to activate cGAS/STING signaling of macrophages, thereby exacerbating the progression of NAFLD.

Regulated Necrosis in Glaucoma: Focus on Ferroptosis and Pyroptosis

Glaucoma is one of the most common causes of irreversible blindness worldwide. This neurodegenerative disease is characterized by progressive and irreversible damage to retinal ganglion cells (RGCs) and optic nerves, which can lead to permanent loss of peripheral and central vision. To date, maintaining long-term survival of RGCs using traditional treatments, such as medication and surgery, remains challenging, as these do not promote optic nerve regeneration. Therefore, it is of great clinical and social significance to investigate the mechanisms of optic nerve degeneration in depth and find reliable targets to provide pioneering methods for the prevention and treatment of glaucoma. Regulated necrosis is a form of genetically programmed cell death associated with the maintenance of homeostasis and disease progression in vivo. An increasing body of innovative evidence has recognized that aberrant activation of regulated necrosis pathways is a common feature in neurodegenerative diseases, such as Alzheimer's, Parkinson's, and glaucoma, resulting in unwanted loss of neuronal cells and function. Among them, ferroptosis and pyroptosis are newly discovered forms of regulated cell death actively involved in the pathophysiological processes of RGCs loss and optic nerve injury. This was shown by a series of in vivo and in vitro studies, and these mechanisms have been emerging as a key new area of scientific research in ophthalmic diseases. In this review, we focus on the molecular mechanisms of ferroptosis and pyroptosis and their regulatory roles in the pathogenesis of glaucoma, with the aim of exploring their implications as potential therapeutic targets and providing new perspectives for better clinical decision-making in glaucoma treatment.

PLCE1 enhances mitochondrial dysfunction to promote GSDME-mediated pyroptosis in doxorubicin-induced cardiotoxicity

BACKGROUND

The therapeutic value and long-term application of doxorubicin (DOX) were hampered by its severe irreversible cardiotoxicity. Phospholipase C epsilon 1 (PLCE 1) was reported as a new member of the phospholipase C (PLC) family which controls the level of phosphoinositides in cells. Pyroptosis is a newly discovered inflammatory type of regulated cell death. Recent studies have consolidated that chemotherapeutic drugs lead to pyroptosis. Additionally, the phosphoinositide signaling system has remarkable effects on the execution of cell death. We aim to investigate the role of PLCE1 and the mechanism of pyroptosis from the context of DOX-induced cardiotoxicity.

METHODS

In the current study, in vitro and in vivo experiments were performed to dissect the underlying mechanism of cardiomyocyte pyroptosis during DOX-induced cardiac injury. The molecular mechanism of PLCE1 was identified by the human cardiomyocyte AC16 cell line and C57BL/6 mouse model.

RESULTS

The results here indicated that PLCE1 high expressed and pyroptotic cell death presented in cardiomyocytes after DOX application, which was negatively correlated to heart function. DOX-induced cell model disclosed pyroptosis mediated by Gasdermin E (GSDME) protein and involved in mitochondrial damage. Conversely, the deletion of PLCE1 ameliorated mitochondrial dysfunction by suppressing ROS accumulation and reversing mitochondrial membrane potential, and then increased cell viability effectively. More importantly, the in vivo experiment demonstrated that inhibition of PLCE1 reduced pyroptotic cell death and improved heart effect.

CONCLUSIONS

We discovered firstly that PLCE1 inhibition protected cardiomyocytes from DOX-induced pyroptotic injury and promoted cardiac function. This information offers a theoretical basis for promising therapy.

TREM2 Deficiency Aggravates NLRP3 Inflammasome Activation and Pyroptosis in MPTP-Induced Parkinson's Disease Mice and LPS-Induced BV2 Cells

Microglia-mediated neuroinflammation plays a crucial role in the pathogenesis of Parkinson's disease (PD). Triggering receptor expressed on myeloid cells 2 (TREM2) confers strong neuroprotective effects in PD by regulating the phenotype of microglia. Recent studies suggest that TREM2 regulates high glucose-induced microglial inflammation through the NLRP3 signaling pathway. This study aimed to investigate the effect of TREM2 on NLRP3 inflammasome activation and neuroinflammation in PD. Mice were injected with AAV-TREM2-shRNA into both sides of the substantia nigra using a stereotactic injection method, followed by intraperitoneal injection of MPTP to establish chronic PD mouse model. Behavioral assessments including the pole test and rotarod test were conducted to evaluate the effects of TREM2 deficiency on MPTP-induced motor dysfunction. Immunohistochemistry of TREM2 and tyrosine hydroxylase (TH), immunohistochemistry and immunofluorescence Iba1, Western blot of NLRP3 inflammasome and its downstream inflammatory factors IL-1β and IL-18, and the key pyroptosis factors GSDMD and GSDMD-N were performed to explore the effect of TREM2 on NLRP3 inflammasome and neuroinflammation. In an in vitro experiment, lentivirus was used to interfere with the expression of TREM2 in BV2 microglia, and then lipopolysaccharide (LPS) and adenopterin nucleoside triphosphate (ATP) were used to stimulate inflammation to construct a cellular inflammation model. The expression differences of NLRP3 inflammasome and its components were detected by qPCR and Western blot. In vivo, TREM2 knockdown aggravated the loss of dopaminergic neuron and the decline of motor function. After TREM2 knockdown, the number of activated microglia was significantly increased, and the expression of cleaved caspase-1, NLRP3 inflammasome, IL-1β, GSDMD, and GSDMD-N was increased. In vitro, TREM2 knockdown aggravated the inflammatory response of BV2 cells stimulated by LPS and promoted the activation of NLRP3 inflammasome through the NF-κB pathway. In addition, TREM2 knockdown also promoted the expression of TLR4/MyD88, an upstream factor of the NF-κB pathway. Our vivo and vitro data showed that TREM2 knockdown promoted NLRP3 inflammasome activation and downstream inflammatory response, promoted pyroptosis, and aggravated dopaminergic neuron loss. TREM2 acts as an anti-inflammatory in PD through the TLR4/MyD88/NF-κB pathway, which extends previous findings and supports the notion that TREM2 ameliorates neuroinflammation in PD.

The roles of pyroptosis in genitourinary diseases

Pyroptosis, a form of programmed cell death distinct from apoptosis and necrosis, is thought to be closely associated with the pathogenesis of diseases. Recently, the association between pyroptosis and urinary diseases has attracted considerable attention, and a comprehensive review focusing on this issue is not available. In this study, we reviewed the role of pyroptosis in the development and progression of benign urinary diseases and urinary malignancies. Based on this, pyroptosis has been implicated in the development of urinary diseases. In summary, this review sheds light on future research directions and provides novel ideas for using pyroptosis as a powerful tool to fight urinary diseases.

Induction of IFIT1/IFIT3 and inhibition of Bcl-2 orchestrate the treatment of myeloma and leukemia via pyroptosis

Induction of pyroptosis is proposed as a promising strategy for the treatment of hematological malignancies, but little is known. In the present study, we find clioquinol (CLQ), an anti-parasitic drug, induces striking myeloma and leukemia cell pyroptosis on a drug screen. RNA sequencing reveals that the interferon-inducible genes IFIT1 and IFIT3 are markedly upregulated and are essential for CLQ-induced GSDME activation and cell pyroptosis. Specifically, IFIT1 and IFIT3 form a complex with BAX and N-GSDME therefore directing N-GSDME translocalization to mitochondria and increasing mitochondrial membrane permeabilization and triggering pyroptosis. Furthermore, venetoclax, an activator of BAX and an inhibitor of Bcl-2, displays strikingly synergistic effects with CLQ against leukemia and myeloma via pyroptosis. This study thus reveals a novel mechanism for mitochondrial GSDME in pyroptosis and it also illustrates that induction of IFIT1/T3 and inhibition of Bcl-2 orchestrate the treatment of leukemia and myeloma via pyroptosis.

Jianpi Antai formula prevents miscarriage by repressing M1 polarization of decidual macrophages through ubiquitination of NLRP3 mediated by MARCH7

ETHNOPHARMACOLOGICAL RELEVANCE

Jianpi Antai Formula (JAF) is an ancient formula from He's gynecology, which has been used clinically for more than 30 years and has significant therapeutic effects on spontaneous abortion (SA). Both macrophage polarization and NLRP3 inflammasome correlate with the occurrence of SA in women with recurrent or threatened miscarriage. Whether JAF prevent SA via mediating activation of decidual macrophage (dMφ) and ubiquitination-associated degradation of NLRP3 remains uncertain.

AIM OF THE STUDY

This study aimed to clarify the effects of JAF on pregnancy outcomes and dMφ polarization at the maternal-fetal interface in an SA mouse model, and use in vivo and invitro methods to explore whether JAF can inhibit M1 polarization of dMφ by up-regulating MARCH7-mediated NLRP3 ubiquitination, thereby preventing SA.

MATERIALS AND METHODS

The CBA/J × DBA/2 mating method was used to establish an SA model and the dMφs of SA mice were isolated and cultured. Th1-, Th2-, Th17- and Treg-related cytokine levels were evaluated using ELISA. qRT-PCR was used to detect the levels of M1/M2 macrophage-related cytokine mRNA in the decidua, and western blotting was used to detect the expression of NLRP3 inflammasome-related proteins in the decidua and placenta. The expression of M1/M2 markers of dMφ was detected using flow cytometry, ASC speck formation was observed using immunofluorescence, and the ubiquitination level of MARCH7-NLRP3 was detected using co-immunoprecipitation.

RESULTS

JAF increased the survival rate of fetuses and the levels of estradiol and progesterone in SA model mice. It also reduced the serum Th1 and Th17-associated cytokine levels and decidual M1 macrophage-associated cytokine levels, while elevating the M2 macrophages in SA mice. NLRP3, caspase-1, ASC, and IL-1β protein expression in the decidua and placenta were also reduced. si-MARCH7 transfection reversed the effect of JAF on inhibiting the formation of the NLRP3 inflammasome and the activation of macrophages in dMφs of SA mice.

CONCLUSION

JAF could effectively prevent and treat SA by repressing M1 polarization of dMφs through NLRP3 ubiquitination and pyroptosis inhibition, which were mediated by MARCH7.

Fufang Zhenzhu Tiaozhi (FTZ) suppression of macrophage pyroptosis: Key to stabilizing rupture-prone plaques

BACKGROUND

Research on the Chinese herbal formula Fufang Zhenzhu Tiaozhi (FTZ) has demonstrated its effectiveness in treating hyperlipidemia and glycolipid metabolic disorders. Additionally, FTZ has shown inhibitory effects on oxidative stress, regulation of lipid metabolism, and reduction of inflammation in these conditions. However, the precise mechanisms through which FTZ modulates macrophage function in atherosclerosis remain incompletely understood. Therefore, this study aims to investigate whether FTZ can effectively stabilize rupture-prone plaques by suppressing macrophage pyroptosis and impeding the development of M1 macrophage polarization in ApoE-/- mice.

METHODS

To assess the impact of FTZ on macrophage function and atherosclerosis in ApoE-/- mice, we orally administered FTZ at a dosage of 1.2 g/kg body weight daily for 14 weeks. Levels of interleukin-18 and interleukin-1β were quantified using ELISA kits to gauge FTZ's influence on inflammation. Total cholesterol content was measured with a Cholesterol Assay Kit to evaluate FTZ's effect on lipid metabolism. Aortic tissues were stained with Oil Red O, and immunohistochemistry techniques were applied to assess atherosclerotic lesions and plaque stability. To evaluate the effects of FTZ on macrophage pyroptosis and oxidative damage, immunofluorescence staining was utilized. Additionally, we conducted an analysis of protein and mRNA expression levels of NLRP3 inflammasome-related genes and macrophage polarization-related genes using RT-PCR and western blotting techniques.

RESULTS

This study illustrates the potential therapeutic effectiveness of FTZ in mitigating the severity of atherosclerosis and improving serum lipid profiles by inhibiting inflammation. The observed enhancements in atherosclerosis severity and inflammation can be attributed to the suppression of NLRP3 inflammasome activity and M1 polarization by FTZ.

CONCLUSION

The current findings indicate that FTZ provides protection against atherosclerosis, positioning it as a promising candidate for novel therapies targeting atherosclerosis and related cardiovascular diseases.

A novel mechanism for regulating lung immune homeostasis: Zukamu granules alleviated acute lung injury in mice by inhibiting NLRP3 inflammasome activation and regulating Th17/Treg cytokine balance

ETHNOPHARMACOLOGICAL RELEVANCE

Acute lung injury (ALI) is a severely acute lung inflammation with high morbidity and mortality. Zukamu granules (ZKMG) is one of the Uygur patent drugs commonly used in clinic, which is included in the National Essential Drugs List (2018 edition). Clinical studies have shown that ZKMG has a significant effect on acute upper respiratory tract infection, and has better anti-inflammatory and antipyretic effects. However, the immunomodulatory mechanism of ZKMG on ALI is still not clear.

AIM OF THE STUDY

The aim of this study is to investigate the lung protective effect and immunomodulatory mechanism of ZKMG on lipopolysaccharide (LPS) -induced ALI mice, and to provide an important basis for the treatment strategy and theoretical basis of ALI.

MATERIALS AND METHODS

First, network pharmacology was used to predict the potential signaling pathways and biological processes of ZKMG related to immunology. Molecular docking technique was used to predict the possibility between the core components of ZKMG acting on NLRP3 protein. In addition, protein levels of F4/80 in lung tissues were assessed by Immunohistochemistry (IHC). The contents of IL-1β, IL-18, IL-17A and IL-10 in the lung tissue and serum, MPO in the lung tissue were detected by enzyme-linked immunosorbent assay (ELISA). Real-time quantitative PCR analysis (RT-qPCR) was used to detect NLRP3 mRNA in lung tissue. Protein levels of NLRP3, Caspase-1, Cleaved caspase-1 p20, ASC, and GSDMD were detected by Western blot (WB).

RESULTS

The results of network pharmacology showed that the immune pathways of ZKMG were mainly Th17 signaling pathway, IL-17 signaling pathway, NOD-like receptor signaling pathway, etc. Molecular docking results showed that the core components of ZKMG had good binding ability to NLRP3 protein. The verification experiments showed that ZKMG can reduce the degree of lung injury, and reduce the level of inflammatory infiltration of neutrophils and macrophages by reducing the content of MPO and F4/80. In addition, ZKMG can reduce NLRP3 mRNA, inhibit the expression of NLRP3/Caspase-1/GSDMD and other related pathway proteins, and reduce inflammatory factors such as IL-1β and IL-18. It can also reduce the content of pro-inflammatory cytokine IL-17A, increase the content of anti-inflammatory cytokine IL-10 in lung tissue.

CONCLUSION

ZKMG can reduce the degree of lung tissue injury in ALI by inhibiting NLRP3/Caspase-1/GSDMD signaling pathway and restoring the IL-17A/IL-10 cytokine balance, and its protective mechanism may be related to the regulation of lung immune homeostasis. It will provide a new strategy for studying the regulation of lung immune homeostasis.

Fine particulate matter aggravates smoking induced lung injury via NLRP3/caspase-1 pathway in COPD

BACKGROUND

Exposure to noxious particles, including cigarette smoke and fine particulate matter (PM2.5), is a risk factor for chronic obstructive pulmonary disease (COPD) and promotes inflammation and cell death in the lungs. We investigated the combined effects of cigarette smoking and PM2.5 exposure in patients with COPD, mice, and human bronchial epithelial cells.

METHODS

The relationship between PM2.5 exposure and clinical parameters was investigated in patients with COPD based on smoking status. Alveolar destruction, inflammatory cell infiltration, and pro-inflammatory cytokines were monitored in the smoking-exposed emphysema mouse model. To investigate the mechanisms, cell viability and death and pyroptosis-related changes in BEAS-2B cells were assessed following the exposure to cigarette smoke extract (CSE) and PM2.5.

RESULTS

High levels of ambient PM2.5 were more strongly associated with high Saint George's respiratory questionnaire specific for COPD (SGRQ-C) scores in currently smoking patients with COPD. Combined exposure to cigarette smoke and PM2.5 increased mean linear intercept and TUNEL-positive cells in lung tissue, which was associated with increased inflammatory cell infiltration and inflammatory cytokine release in mice. Exposure to a combination of CSE and PM2.5 reduced cell viability and upregulated NLRP3, caspase-1, IL-1β, and IL-18 transcription in BEAS-2B cells. NLRP3 silencing with siRNA reduced pyroptosis and restored cell viability.

CONCLUSIONS

PM2.5 aggravates smoking-induced airway inflammation and cell death via pyroptosis. Clinically, PM2.5 deteriorates quality of life and may worsen prognosis in currently smoking patients with COPD.

Epigenetic regulation of diverse cell death modalities in cancer: a focus on pyroptosis, ferroptosis, cuproptosis, and disulfidptosis

Tumor is a local tissue hyperplasia resulted from cancerous transformation of normal cells under the action of various physical, chemical and biological factors. The exploration of tumorigenesis mechanism is crucial for early prevention and treatment of tumors. Epigenetic modification is a common and important modification in cells, including DNA methylation, histone modification, non-coding RNA modification and m6A modification. The normal mode of cell death is programmed by cell death-related genes; however, recent researches have revealed some new modes of cell death, including pyroptosis, ferroptosis, cuproptosis and disulfidptosis. Epigenetic regulation of various cell deaths is mainly involved in the regulation of key cell death proteins and affects cell death by up-regulating or down-regulating the expression levels of key proteins. This study aims to investigate the mechanism of epigenetic modifications regulating pyroptosis, ferroptosis, cuproptosis and disulfidptosis of tumor cells, explore possible triggering factors in tumor development from a microscopic point of view, and provide potential targets for tumor therapy and new perspective for the development of antitumor drugs or combination therapies.

Inhibition of PI3K p110δ rebalanced Th17/Treg and reduced macrophages pyroptosis in LPS-induced sepsis

Sepsis is a systemic inflammatory response syndrome caused by trauma or infection, which can lead to multiple organ dysfunction. In severe cases, sepsis can also progress to septic shock and even death. Effective treatments for sepsis are still under development. This study aimed to determine if targeting the PI3K/Akt signaling with CAL-101, a PI3K p110δ inhibitor, could alleviate lipopolysaccharide (LPS)-induced sepsis and contribute to immune tolerance. Our findings indicated that CAL-101 treatment improved survival rates and alleviated the progression of LPS-induced sepsis. Compared to antibiotics, CAL-101 not only restored the Th17/regulatory T cells (Treg) balance but also enhanced Treg cell function. Additionally, CAL-101 promoted type 2 macrophage (M2) polarization, inhibited TNF-α secretion, and increased IL-10 secretion. Moreover, CAL-101 treatment reduced pyroptosis in peritoneal macrophages by inhibiting caspase-1/gasdermin D (GSDMD) activation. This study provides a mechanistic basis for future clinical exploration of targeted therapeutics and immunomodulatory strategies in the treatment of sepsis.

Hydralazine loaded nanodroplets combined with ultrasound-targeted microbubble destruction to induce pyroptosis for tumor treatment

Pyroptosis, a novel type of programmed cell death (PCD), which provides a feasible therapeutic option for the treatment of tumors. However, due to the hypermethylation of the promoter, the critical protein Gasdermin E (GSDME) is lacking in the majority of cancer cells, which cannot start the pyroptosis process and leads to dissatisfactory therapeutic effects. Additionally, the quick clearance, systemic side effects, and low concentration at the tumor site of conventional pyroptosis reagents restrict their use in clinical cancer therapy. Here, we described a combination therapy that induces tumor cell pyroptosis via the use of ultrasound-targeted microbubble destruction (UTMD) in combination with DNA demethylation. The combined application of UTMD and hydralazine-loaded nanodroplets (HYD-NDs) can lead to the rapid release of HYD (a demethylation drug), which can cause the up-regulation of GSDME expression, and produce reactive oxygen species (ROS) by UTMD to cleave up-regulated GSDME, thereby inducing pyroptosis. HYD-NDs combined with ultrasound (US) group had the strongest tumor inhibition effect, and the tumor inhibition rate was 87.15% (HYD-NDs group: 51.41 ± 3.61%, NDs + US group: 32.73%±7.72%), indicating that the strategy had a more significant synergistic anti-tumor effect. In addition, as a new drug delivery carrier, HYD-NDs have great biosafety, tumor targeting, and ultrasound imaging performance. According to the results, the combined therapy reasonably regulated the process of tumor cell pyroptosis, which offered a new strategy for optimizing the therapy of GSDME-silenced solid tumors.

Mechanism of astragaloside IV regulating NLRP3 through LOC102555978 to attenuate cerebral ischemia reperfusion induced microglia pyroptosis

Astragaloside IV(ASⅣ), the main component of Radix Astragali, has been used to treat cerebral ischemia reperfusion injury (CIRI). However, the molecular mechanism of ASIV in CIRI needs to be further elucidated. Long non-coding RNA (lncRNA) is considered to be an important kind of regulatory molecule in CIRI. In this work, the biological effect and molecular mechanism of ASIV in CIRI through lncRNA were analyzed by using rat middle cerebral artery occlusion and reperfusion (MCAO/R) model and primary rat microglia (RM) cells oxygen and glucose deprivation/reoxygenation (OGD/R) model. The neurological deficit score was evaluated, the volume of cerebral infarction was calculated, and pyroptosis related molecules were detected by qPCR and western blot. Then, high-throughput sequencing was performed in sham and MCAO/R groups. The competitive endogenous RNA (ceRNA) networks associated with pyroptosis were constructed by functional enrichment analysis. CCK-8 detection of cell survival rate, qPCR and western blot were used to determine the specific molecular mechanism of ASⅣ through ceRNA in vitro. Results showed thatASⅣ could decrease the neurological deficit score, reduce the volume of cerebral infarction, inhibit inflammatory reaction and pyroptosis in MCAO/R model rats. Next, the ceRNA network was established, including the LOC102555978/miR-3584-5p/NLRP3 regulatory network. In vitro experiments showed that LOC102555978 promotes NLRP3 mediated pyroptosis of RM cells through sponge adsorption of miR-3584-5p, which may provide a potential therapeutic target for post-CIRI inflammation regulation. ASⅣ could inhibit pyroptosis of RM cells by down-regulating LOC102555978. LOC102555978/miR-3584-5p/NLRP3 may be the molecular mechanism of ASⅣ's CIRI protective effect.

miR-29b-3p regulates cardiomyocytes pyroptosis in CVB3-induced myocarditis through targeting DNMT3A

BACKGROUND

Viral myocarditis (VMC) is a disease resulting from viral infection, which manifests as inflammation of myocardial cells. Until now, the treatment of VMC is still a great challenge for clinicians. Increasing studies indicate the participation of miR-29b-3p in various diseases. According to the transcriptome sequencing analysis, miR-29b-3p was markedly upregulated in the viral myocarditis model. The purpose of this study was to investigate the role of miR-29b-3p in the progression of VMC.

METHODS

We used CVB3 to induce primary cardiomyocytes and mice to establish a model of viral myocarditis. The purity of primary cardiomyocytes was identified by immunofluorescence. The cardiac function of mice was detected by Vevo770 imaging system. The area of inflammatory infiltration in heart tissue was shown by hematoxylin and eosin (H&E) staining. The expression of miR-29b-3p and DNMT3A was detected by quantitative real time polymerase chain reaction (qRT-PCR). The expression of a series of pyroptosis-related proteins was detected by western blot. The role of miR-29b-3p/DNMT3A in CVB3-induced pyroptosis of cardiomyocytes was studied in this research.

RESULTS

Our data showed that the expression of miR-29b-3p was upregulated in CVB3-induced cardiomyocytes and heart tissues in mice. To explore the function of miR-29b-3p in CVB3-induced VMC, we conducted in vivo experiments by knocking down the expression of miR-29b-3p using antagomir. We then assessed the effects on mice body weight, histopathology changes, myocardial function, and cell pyroptosis in heart tissues. Additionally, we performed gain/loss-of-function experiments in vitro to measure the levels of pyroptosis in primary cardiomyocytes. Through bioinformatic analysis, we identified DNA methyltransferases 3A (DNMT3A) as a potential target gene of miR-29b-3p. Furthermore, we found that the expression of DNMT3A can be modulated by miR-29b-3p during CVB3 infection.

CONCLUSIONS

Our results demonstrate a correlation between the expression of DNMT3A and CVB3-induced pyroptosis in cardiomyocytes. These findings unveil a previously unidentified mechanism by which CVB3 induces cardiac injury through the regulation of miR-29b-3p/DNMT3A-mediated pyroptosis.

Gypenoside XLIX alleviates acute liver injury: Emphasis on NF-κB/PPAR-α/NLRP3 pathways

Liver is one of the vital organs in the human body and liver injury will have a very serious impact on human damage. Gypenoside XLIX is a PPAR-α activator that inhibits the activation of the NF-κB signaling pathway. The components of XLIX have pharmacological effects such as cardiovascular protection, antihypoxia, anti-tumor and anti-aging. In this study, we used cecum ligation and puncture (CLP) was used to induce in vivo mice hepatic injury, and lipopolysaccharide (LPS)-induced inflammation in RAW264.7 cells, evaluated whether Gypenoside XLIX could have a palliative effect on sepsis-induced acute liver injury via NF-κB/PPAR-α/NLRP3. In order to gain insight into these mechanisms, six groups were created in vivo: the Contol group, the Sham group, the CLP group, the CLP + XLIX group (40 mg/kg) and the Sham + XLIX (40 mg/kg) group, and the CLP + DEX (2 mg/kg) group. Three groups were created in vitro: Control, LPS, LPS + XLIX (40 μM). The analytical methods used included H&E staining, qPCR, reactive oxygen species (ROS), oil red O staining, and Western Blot. The results showed that XLIX attenuated hepatic inflammatory injury in mice with toxic liver disease through inhibition of the TLR4-mediated NF-κB pathway, attenuated lipid accumulation through activation of PPAR-α, and attenuated hepatic pyroptosis by inhibiting NLRP3 production. Regarding the imbalance between oxidative and antioxidant defenses due to septic liver injury, XLIX reduced liver oxidative stress-related biomarkers (ALT, AST), reduced ROS accumulation, decreased the amount of malondialdehyde (MDA) produced by lipid peroxidation, and increased the levels of antioxidant enzymes such as glutathione (GSH) and catalase (CAT). Our results demonstrate that XLIX can indeed attenuate septic liver injury. This is extremely important for future studies on XLIX and sepsis, and provides a potential pathway for the treatment of acute liver injury.

Up-regulation of HSP90α in HDM-induced asthma causes pyroptosis of airway epithelial cells by activating the cGAS-STING-ER stress pathway

Heat Shock protein 90 α (HSP90α), an main subtype of chaperone protein HSP90, involves important biological functions such as DNA damage repair, protein modification, innate immunity. However, the potential role of HSP90α in asthma occurrence and development is still unclear. This study aimed to elucidate the underlying mechanism of HSP90α in asthma by focusing on the cGAS-STING-Endoplasmic Reticulum stress pathway in inflammatory airway epithelial cell death (i.e., pyroptosis; inflammatory cell death). To accomplish that, we modeled allergen exposure in C57/6BL mice and bronchial epithelial cells with house dust mite. Protein technologies and immunofluorescence utilized to study the expression of HSP90α, activation of cGAS-STING pathway and pyroptosis. The effect of inhibitors on HDM-exposed mice detected by histological techniques and examination of bronchoalveolar lavage fluid. Results showed that HSP90α promotes asthma inflammation via pyroptosis and activation of the cGAS-STING-ER stress pathway. Treatment with the HSP90 inhibitor tanespimycin (17-AAG) significantly relieved airway inflammation and abrogated the effect of HSP90α on pyroptosis and cGAS-STING-ER stress in vitro and in vivo models of HDM. Further data indicated that up-regulation of HSP90α stabilized STING through interaction, which increased localization of STING on the ER. Activation of STING triggered ER stress and leaded to pyroptosis-related airway inflammation. The finding showed the potential role of pyroptosis caused by dysregulation of HSP90α on airway epithelial cells in allergic inflammation, suggested that targeting HSP90α in airway epithelial cells might prove to be a potential additional treatment strategy for asthma.

Dapagliflozin prevents kidney podocytes pyroptosis via miR-155-5p/HO-1/NLRP3 axis modulation

Diabetic nephropathy (DN) is a significant clinical microvascular complication associated with diabetes mellitus (DM), and end-stage diabetes giving rise to kidney failure is developing into the major etiological factor of chronic kidney failure. Dapagliflozin is reported to limit podocyte damage in DM, which has proven to protect against renal failure. Mounting evidence has demonstrated that pyroptosis is associated with DM progression. Nevertheless, whether pyroptosis causes DN and the underlying molecular pathways remain obscure. In this study, we aimed to explore the antipyroptotic attributes of dapagliflozin and elucidate the underlying mechanisms of kidney damage in diabetes. In vivo, experiments were conducted in streptozotocin (STZ)-induced type 2 diabetic mice, which were administered dapagliflozin via gavage for 6 weeks. Subsequently, the specific organizational characteristics and expression of pyroptosis-related genes were evaluated. Intragastric dapagliflozin administration markedly reduced renal tissue injury. Meanwhile, dapagliflozin also attenuated the expression level of pyroptosis associated genes, including ASC, cleaved Caspase-1, GSDMD N-termini, NLRP3, IL-18, and IL-1β in renal tissue of dapagliflozin-treated animals. Similar antipyroptotic effects were observed in palmitic acid (PA)-treated mouse podocytes. We also found that heme oxygenase 1 (HO-1) enhanced the protection of mouse podocyte clone 5 cells (MPC5). Moreover, miR-155-5p inhibition increased pyroptosis in PA-treated MPC5 cells, suggesting that miR-155-5p acts as an endogenous stimulator that increases HO-1 expression and reduces pyroptosis. Hence, our findings imply that dapagliflozin inhibits podocyte pyroptosis via the miR-155-5p/HO-1/NLRP3 axis in DM. Furthermore, dapagliflozin substitution may be regarded as an effective strategy for preventing pyroptosis in the kidney, including a therapeutic option for treating pyroptosis-related DN.

Caspase-3/Gasdermin E-mediated pyroptosis contributes to Ricin toxin-induced inflammation

Ricin toxin (RT) is highly cytotoxic and can release a considerable amount of pro-inflammatory factors due to depurination, causing excessive inflammation that may aggravate the harm to the body. Pyroptosis, a type of gasdermin-mediated cell death, is a contributor to the exacerbation of inflammation. Accumulating evidence indicate that pyroptosis plays a significant role in the pathogen infection and tissue injury, suggesting a potential correlation between pyroptosis and RT-induced inflammation. Here, we aim to demonstrate this correlation and explore its molecular mechanisms. Results showed that RT triggers mouse alveolar macrophage MH-S cells pyroptosis by activating caspase-3 and cleaving Gasgermin E (GSDME). In contrast, inhibition of caspase-3 with Z-DEVD-FMK (inhibitor of caspase-3) or knockdown of GSDME attenuates this process, suggesting the essential role of caspase-3/GSDME-mediated pyroptosis in contributing to RT-induced inflammation. Collectively, our study enhances our understanding of a novel mechanism of ricin cytotoxicity, which may emerge as a potential target in immunotherapy to control the RT-induced inflammation.

Hyperthermia and cisplatin combination therapy promotes caspase-8 accumulation and activation to enhance apoptosis and pyroptosis in cancer cells

BACKGROUND

Hyperthermia can play a synergistic role with chemotherapy in combination therapy. Although the association between caspase activation, apoptosis, and pyroptosis have been published for both cisplatin (CDDP) and hyperthermia therapies independently, the interactions between these molecular pathways in combination therapy are unknown. The present study aimed to investigate the possible interactions between caspase 8 activation, apoptosis, and pyroptosis in combination therapy.

METHODS

Cells were treated with CDDP (15 µg/ml), followed by hyperthermia at optimized temperature (42.5 °C) in water-bath. After combination therapy, cell viability was analyzed by CCK-8, and cell death was analyzed by Annexin-V-FITC/PI and caspases activation. Immuno-staining and co-immuno-precipitation were used to examine the interaction between p62 and caspase-8. Pyroptosis was investigated by western blotting and transmission electron microscopy. E3 ligase Cullin 3 was knockdown by siRNA. In addition, caspase-8 activation was modulated by CRISPR-Cas9 gene-editing or pharmacological inhibition.

RESULTS

Combination therapy promoted K63-linked polyubiquitination of caspase-8 and cellular accumulation of caspase-8. In turn, polyubiquitinated caspase-8 interacted with p62 and led to the activation of caspase-3. Knockdown of the E3 ligase Cullin 3 by siRNA reduced caspase-8 polyubiquitination and activation. In addition, combination therapy induced release of the pore-forming N-terminus from gasdermins and promoted pyroptosis along with caspase-8 accumulation and activation. Knockdown of caspase-8 by CRISPR/Cas9 based gene editing reduced the sensitivity of tumor cells to apoptosis and pyroptosis.

CONCLUSIONS

Our study presented a novel mechanism in which hyperthermia synergized with chemotherapy in promoting apoptosis and pyroptosis in a caspase-8 dependent manner.

IRF4 Knockdown Inhibits the Chronic Rhinosinusitis Without Nasal Polyps Development by Regulating NLRP3/Caspase-1/GSDMD-Mediated Pyroptosis

Chronic rhinosinusitis without nasal polyps (CRSsNP) is a CRS phenotype. However, the mechanisms of CRSsNP remains unclear. Differentially expressed genes (DEGs) were obtained from the GSE36830 and GSE198950 datasets through the GEO2R tool. The six hub genes were screened by the protein-protein interaction (PPI) network analysis and Cytoscape software. Then we constructed the mouse models of CRS and verified the expression levels of hub genes by reverse transcription quantitative PCR (RT-qPCR). Hematoxylin-eosin (HE) staining was employed to observe pathological alterations in mouse tissues. Casepase-3 expression was detected by immunohistochemistry (IHC). The levels of TNF-α, IL-12, IL-6, IL-1β, LDH, and IL-18 were evaluated using enzyme-linked immunosorbent assay (ELISA). Pyroptosis-related protein expressions were measured by western blotting. Cell counting kit-8 (CCK-8) and flow cytometry were performed to assess the proliferation and apoptosis of lipopolysaccharide (LPS)-induced NP69 cells. Six hub DEGs were identified. The expression levels of IRF4, IKZF1, and CD79A were obviously increased in CRSsNP, while those of ADH6, ADH1A, and LDHC were significantly decreased. IRF4 knockdown attenuated the pathologic features of CRSsNP. IRF4 knockdown reduced levels of the TNF-α, IL-12, IL-6 IL-1β, LDH, and IL-18 as well as the proteins expression of Casepase-1, GSDMD, and NLRP3 both in vivo and in vitro, implying that inflammation and pyroptosis were inhibited. IRF4 knockdown hinders the development of CRSsNP by inhibiting the inflammatory response and NLRP3/Caspase-1/GSDMD-mediated pyroptosis, which offers novel promising treatment strategies for clinical intervention.

EGFR of platelet regulates macrophage activation and bacterial phagocytosis function

BACKGROUND

Beyond their crucial role in hemostasis, platelets possess the ability to regulate inflammation and combat infections through various mechanisms. Stringent control of macrophage activation is essential during innate immune responses in sepsis. Macrophages are considered crucial phagocytic cells that aid in the elimination of pathogens. Platelet interactions with monocytes-macrophages are known to be significant in the response against bacterial infections, but the primary mediator driving these interactions remains unclear. EGFR plays critical role in the regulation of inflammation and infection through various mechanisms.

RESULTS

The overexpression of platelets by thrombopoietin (TPO) leads to the sequestration of both pro-inflammatory (IL-6/IL-1) and anti-inflammatory (IL-10) cytokines in the organ tissue of septic mice. Epidermal growth factor receptor (EGFR) is critical for platelet activation in sepsis. EGFR-licensed platelets enhance macrophage immune function, including the production of reactive oxygen species (ROS) and the clearance of bacteria. Platelet EGFR also induces M1 macrophage polarization by increasing the expression of inducible nitric oxide synthase (iNOS) and CD64.

CONCLUSION

EGFR can activate platelet immune function. Moreover, activated platelets efficiently regulate bacterial phagocytosis and pro-inflammatory function of macrophages through an EGFR-dependent pathway.

Exploration of the mode of death and potential death mechanisms of nucleus pulposus cells

Intervertebral disc degeneration (IVDD) is a common chronic orthopaedic disease in orthopaedics that imposes a heavy economic burden on people and society. Although it is well established that IVDD is associated with genetic susceptibility, ageing and obesity, its pathogenesis remains incompletely understood. Previously, IVDD was thought to occur because of excessive mechanical loading leading to destruction of nucleus pulposus cells (NPCs), but studies have shown that IVDD is a much more complex process associated with inflammation, metabolic factors and NPCs death and can involve all parts of the disc, characterized by causing NPCs death and extracellular matrix (ECM) degradation. The damage pattern of NPCs in IVDD is like that of some programmed cell death, suggesting that IVDD is associated with programmed cell death. Although apoptosis and pyroptosis of NPCs have been studied in IVDD, the pathogenesis of intervertebral disc degeneration can still not be fully elucidated by using only traditional cell death modalities. With increasing research, some new modes of cell death, PANoptosis, ferroptosis and senescence have been found to be closely related to intervertebral disc degeneration. Among these, PANoptosis combines essential elements of pyroptosis, apoptosis and necroptosis to form a highly coordinated and dynamically balanced programmed inflammatory cell death process. Furthermore, we believe that PANoptosis may also crosstalk with pyroptosis and senescence. Therefore, we review the progress of research on multiple deaths of NPCs in IVDD to provide guidance for clinical treatment.

Periplogenin inhibits pyroptosis of fibroblastic synoviocytes in rheumatoid arthritis through the NLRP3/Caspase-1/GSDMD signaling pathway

Although the pathogenesis of rheumatoid arthritis (RA) remains unclear, an increasing number of studies have confirmed that pyroptosis of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS) is an important factor affecting the progression of RA. Periplogenin (PPN) is a natural cardiac glycoside; reportedly, it exerts anti-inflammatory and analgesic effects in diseases by inhibiting cell growth and migration. This study aimed to determine the effect of PPN on the growth, migration, and invasion of RA-FLS and the potential mechanism of pyroptosis regulation. We discovered that PPN could inhibit the migration and invasion abilities of RA-FLS and block their growth cycle, down-regulate the secretion and activation of NLRP3, Caspase-1, GSDMD, IL-1β, and IL-18, and reduce the number of pyroptosis. In summary, PPN inhibited pyroptosis, reduced the release of inflammatory factors, and improved RA-FLS inflammation by regulating the NLRP3/Caspase-1/GSDMD signaling pathway.

Unveiling the role of PD-L1 in vascular endothelial dysfunction: Insights into the mtros/NLRP3/caspase-1 mediated pyroptotic pathway

BACKGROUND

Programmed death ligand-1(PD-L1) has been postulated to play a crucial role in the regulation of barrier functions of the vascular endothelium, yet how this novel molecule mediates dysfunction in endothelial cells (ECs) during acute lung injury (ALI) remains largely unknown.

METHODS

PD-L1 siRNA and plasmids were synthesized and applied respectively to down- or up-regulate PD-L1 expression in human lung microvascular endothelial cells (HMVECs). RNA sequencing was used to explore the differentially expressed genes following PD-L1 overexpression. The expression levels of tight junction proteins (ZO-1 and occludin) and the signaling pathways of NLRP-3/caspase-1/pyroptosis were analyzed. A mouse model of indirect ALI was established through hemorrhagic shock (HEM) followed by cecal ligation and puncture (CLP), enabling further investigation into the effects of intravenous delivery of PD-L1 siRNA.

RESULTS

A total of 1502 differentially expressed genes were identified, comprising 532 down-regulated and 970 up-regulated genes in ECs exhibiting PD-L1overexpression. Enrichment of PD-L1-correlated genes were observed in the NOD-like receptor signaling pathway and the TNF signaling pathway. Western blot assays confirmed that PD-L1 overexpression elevated the expression of NLRP3, cleaved-caspase-1, ASC and GSDMD, and concurrently diminished the expression of ZO-1 and occludin. This overexpression also enhanced mitochondrial oxidative phosphorylation and mitochondrial reactive oxygen species (mtROS) production. Interestingly, mitigating mitochondrial dysfunction with mitoQ partially countered the adverse effects of PD-L1 on the functionality of ECs. Furthermore, intravenous administration of PD-L1 siRNA effectively inhibited the activation of the NLRP3 inflammasome and pyroptosis in pulmonary ECs, subsequently ameliorating lung injury in HEM/CLP mice.

CONCLUSION

PD-L1-mediated activation of the inflammasome contributes significantly to the disruption of tight junction and induction of pyroptosis in ECs, where oxidative stress associated with mitochondrial dysfunction serves as a pivotal mechanism underpinning these effects.

Emodin activates autophagy to suppress oxidative stress and pyroptosis via mTOR-ULK1 signaling pathway and promotes multi-territory perforator flap survival

BACKGROUND

Multi-territory perforator flap reconstruction has been proven effective in treating large skin and soft tissue defects in clinical settings. However, in view of that the multi-territory perforator flap is prone to partial postoperative necrosis, increasing its survival is the key to the success of reconstruction. In this study, we aimed to clarify the effect of emodin on multi-territory perforator flap survival.

METHODS

Flap survival was assessed by viability area analysis, infrared laser imaging detector, HE staining, immunohistochemistry, and angiography. Western blotting, immunofluorescence assays, and real-time fluorescent quantitative PCR were performed to detect the indicators of oxidative stress, pyroptosis and autophagy.

RESULTS

After emodin treatment, the multi-territory perforator flap showed a significantly increased survival rate, which was shown to be closely related to the inhibition of oxidative stress and pyroptosis and enhanced autophagy. Meanwhile, the use of autophagy inhibitor 3 MA was found to reverse the inhibitory effects of emodin on oxidative stress and pyroptosis and weaken the improving effect of emodin on flap survival, suggesting that autophagy plays a critical role in emodin-treated flaps. Interestingly, our mechanistic investigations revealed that the positive effect of emodin on multi-territory perforator flap was attributed to the mTOR-ULK1 signaling pathway activation.

CONCLUSIONS

Emodin can inhibit oxidative stress and pyroptosis by activating autophagy via the mTOR-ULK1 pathway, thereby improving the multi-territory perforator flap survival.