Mitochondrial ROS promote macrophage pyroptosis by inducing GSDMD oxidation

Mechanisms and therapeutic potential of disulphidptosis in cancer

SLC7A11 plays a pivotal role in tumour development by facilitating cystine import to enhance glutathione synthesis and counteract oxidative stress. Disulphidptosis, an emerging form of cell death observed in cells with high expression of SLC7A11 under glucose deprivation, is regulated through reduction-oxidation reactions and disulphide bond formation. This process leads to contraction and collapse of the F-actin cytoskeleton from the plasma membrane, ultimately resulting in cellular demise. Compared to other forms of cell death, disulphidptosis exhibits distinctive characteristics and regulatory mechanisms. This mechanism provides novel insights and innovative strategies for cancer treatment while also inspiring potential therapeutic approaches for other diseases. Our review focuses on elucidating the molecular mechanism underlying disulphidptosis and its connection with the actin cytoskeleton, identifying alternative metabolic forms of cell death, as well as offering insights into disulphidptosis-based cancer therapy. A comprehensive understanding of disulphidptosis will contribute to our knowledge about fundamental cellular homeostasis and facilitate the development of groundbreaking therapies for disease treatment.

Chitosan oligosaccharides alleviate macrophage pyroptosis and protect sepsis mice via activating the Nrf2/GPX4 pathway

In the process of sepsis, excessive occurrence of pyroptosis, a form of programmed cell death acting as a defense mechanism against pathogens, can disrupt immune responses, thus leading to tissue damage and organ dysfunction. Chitosan oligosaccharide (COS), derived from chitosan degradation, has demonstrated diverse beneficial effects. However, its impact on sepsis-induced pyroptosis remains unexplored. In the present study, ATP/LPS was utilized to induce canonical-pyroptosis in THP-1 cells, while bacterial outer membrane vesicles (OMV) were employed to trigger non-canonical pyroptosis in RAW264.7 cells. Our results revealed a dose-dependent effect of COS on both types of pyroptosis. This was evidenced by a reduction in the expression of pro-inflammatory cytokines, as well as crucial regulatory proteins involved in pyroptosis. In addition, COS inhibited the cleavage of caspase-1 and GSDMD, and reduced ASC oligomerization. The underlying mechanism revealed that COS acts an antioxidant, reducing the release of pyroptosis-induced ROS and malondialdehyde (MDA) by upregulation the expression and promoting the nuclear translocation of nuclear factor erythroid-2-related factor 2 (Nrf2), which led to an elevation of glutathione peroxidase 4 (GPX4) and superoxide dismutase (SOD). Notably, the actions of COS were completely reversed by the Nrf2 inhibitor. Consequently, COS intervention increased the survival rate of sepsis.

Gasdermin D cysteine residues synergistically control its palmitoylation-mediated membrane targeting and assembly

Gasdermin D (GSDMD) executes the cell death program of pyroptosis by assembling into oligomers that permeabilize the plasma membrane. Here, by single-molecule imaging, we elucidate the yet unclear mechanism of Gasdermin D pore assembly and the role of cysteine residues in GSDMD oligomerization. We show that GSDMD preassembles at the membrane into dimeric and trimeric building blocks that can either be inserted into the membrane, or further assemble into higher-order oligomers prior to insertion into the membrane. The GSDMD residues Cys39, Cys57, and Cys192 are the only relevant cysteines involved in GSDMD oligomerization. S-palmitoylation of Cys192, combined with the presence of negatively-charged lipids, controls GSDMD membrane targeting. Simultaneous Cys39/57/192-to-alanine (Ala) mutations, but not Ala mutations of Cys192 or the Cys39/57 pair individually, completely abolish GSDMD insertion into artificial membranes as well as into the plasma membrane. Finally, either Cys192 or the Cys39/Cys57 pair are sufficient to enable formation of GSDMD dimers/trimers, but they are all required for functional higher-order oligomer formation. Overall, our study unveils a cooperative role of Cys192 palmitoylation-mediated membrane binding and Cys39/57/192-mediated oligomerization in GSDMD pore assembly. This study supports a model in which Gasdermin D oligomerization relies on a two-step mechanism mediated by specific cysteine residues.

An Overview of Hexavalent Chromium-Induced Necroptosis, Pyroptosis, and Ferroptosis

Heavy metals are common environmental industrial pollutants. Due to anthropogenic activity, chromium, especially its hexavalent form [Cr(VI)], is a widespread environmental contaminant that poses a threat to human health. In this review paper, we summarize the currently reported molecular mechanisms involved in chromium toxicity with a focus on the induction of pro-inflammatory non-apoptotic cell death pathways such as necroptosis, pyroptosis, and ferroptosis. The review highlights the ability of chromium to induce necroptosis, pyroptosis, and ferroptosis revealing the signaling pathways involved. Cr(VI) can induce RIPK1/RIPK3-dependent necroptosis both in vitro and in vivo. Chromium toxicity is associated with pyroptotic NLRP3 inflammasome/caspase-1/gasdermin D-dependent secretion of IL-1β and IL-18. Furthermore, this review emphasizes the role of redox imbalance and intracellular iron accumulation in Cr(VI)-induced ferroptosis. Of note, the crosstalk between the investigated lethal subroutines in chromium-induced toxicity is primarily mediated by reactive oxygen species (ROS), which are suggested to act as a rheostat determining the cell death pathway in cells exposed to chromium. The current study provides novel insights into the pro-inflammatory effects of chromium, since necroptosis, pyroptosis, and ferroptosis affect inflammation owing to their immunogenic properties linked primarily with damage-associated molecular patterns. Inhibition of these non-apoptotic lethal subroutines can be considered a therapeutic strategy to reduce the toxicity of heavy metals, including chromium.

Glucose metabolite methylglyoxal induces vascular endothelial cell pyroptosis via NLRP3 inflammasome activation and oxidative stress in vitro and in vivo

Methylglyoxal (MGO), a reactive dicarbonyl metabolite of glucose, plays a prominent role in the pathogenesis of diabetes and vascular complications. Our previous studies have shown that MGO is associated with increased oxidative stress, inflammatory responses and apoptotic cell death in endothelial cells (ECs). Pyroptosis is a novel form of inflammatory caspase-1-dependent programmed cell death that is closely associated with the activation of the NOD-like receptor 3 (NLRP3) inflammasome. Recent studies have shown that sulforaphane (SFN) can inhibit pyroptosis, but the effects and underlying mechanisms by which SFN affects MGO-induced pyroptosis in endothelial cells have not been determined. Here, we found that SFN prevented MGO-induced pyroptosis by suppressing oxidative stress and inflammation in vitro and in vivo. Our results revealed that SFN dose-dependently prevented MGO-induced HUVEC pyroptosis, inhibited pyroptosis-associated biochemical changes, and attenuated MGO-induced morphological alterations in mitochondria. SFN pretreatment significantly suppressed MGO-induced ROS production and the inflammatory response by inhibiting the NLRP3 inflammasome (NLRP3, ASC, and caspase-1) signaling pathway by activating Nrf2/HO-1 signaling. Similar results were obtained in vivo, and we demonstrated that SFN prevented MGO-induced oxidative damage, inflammation and pyroptosis by reversing the MGO-induced downregulation of the NLRP3 signaling pathway through the upregulation of Nrf2. Additionally, an Nrf2 inhibitor (ML385) noticeably attenuated the protective effects of SFN on MGO-induced pyroptosis and ROS generation by inhibiting the Nrf2/HO-1 signaling pathway, and a ROS scavenger (NAC) and a permeability transition pore inhibitor (CsA) completely reversed these effects. Moreover, NLRP3 inhibitor (MCC950) and caspase-1 inhibitor (VX765) further reduced pyroptosis in endothelial cells that were pretreated with SFN. Collectively, these findings broaden our understanding of the mechanism by which SFN inhibits pyroptosis induced by MGO and suggests important implications for the potential use of SFN in the treatment of vascular diseases.

QBT improved cognitive dysfunction in rats with vascular dementia by regulating the Nrf2/xCT/GPX4 and NLRP3/Caspase-1/GSDMD pathways to inhibit ferroptosis and pyroptosis of neurons

BACKGROUND

The novel phthalein component QBT, extracted from Ligusticum chuanxiong, shows promising biological activity against cerebrovascular diseases. This study focused on ferroptosis and pyroptosis to explore the effects of QBT on nerve injury, cognitive dysfunction, and related mechanisms in a rat model of vascular dementia (VaD).

METHODS

We established a rat model of VaD and administered QBT as a treatment. Cognitive dysfunction in VaD rats was evaluated using novel object recognition and Morris water maze tests. Neuronal damage and loss in the brain tissues of VaD rats were assessed with Nissl staining and immunofluorescence. Furthermore, we investigated the neuroprotective mechanisms of QBT by modulating the nuclear factor erythroid 2-related factor 2 (Nrf2)/cystine-glutamate antiporter (xCT)/glutathione peroxidase 4 (GPX4) and Nod-like receptor family pyrin domain-containing 3 (NLRP3)/cysteine-requiring aspartate protease-1 (Caspase-1)/Gasdermin D (GSDMD) pathways to inhibit ferroptosis and pyroptosis both in vivo and in vitro.

RESULTS

Our findings indicated that QBT significantly ameliorated neuronal damage and cognitive dysfunction in VaD rats. Additionally, QBT reversed abnormal changes associated with ferroptosis and pyroptosis in the brains of VaD rats, concurrently up-regulating the Nrf2/xCT/GPX4 pathway and down-regulating the NLRP3/Caspase-1/GSDMD pathway to inhibit ferroptosis and pyroptosis in neuronal cells, thereby exerting a neuroprotective role.

CONCLUSION

In summary, QBT effectively mitigated neuronal damage and cognitive dysfunction in VaD rats, demonstrating a neuroprotective effect by inhibiting ferroptosis and pyroptosis in neuronal cells. This study offers a novel perspective and theoretical foundation for the future development of drugs targeting VaD.

BRD3308 suppresses macrophage oxidative stress and pyroptosis via upregulating acetylation of H3K27 in sepsis-induced acute lung injury

Background

Sepsis-induced acute lung injury (ALI) leads to severe hypoxemia and respiratory failure, contributing to poor prognosis in septic patients. Endotoxin dissemination triggers oxidative stress and the release of inflammatory cytokines in macrophages, initiating diffuse alveolar damage. The role of epigenetic histone modifications in organ injury is increasingly recognized. The present study aimed to investigate the use of a histone modification inhibitor to alleviate sepsis-induced ALI, revealing a new strategy for improving sepsis patient survival.

Methods

In vivo models of ALI were established through the intraperitoneal injection of lipopolysaccharide and cecal ligation and puncture surgery. Furthermore, the disease process was simulated in vitro by stimulating Tamm-Horsfall protein-1 (THP-1) cells with lipopolysaccharide. Hematoxylin and eosin staining, blood gas analysis and pulmonary function tests were utilized to assess the extent of lung tissue damage. Western blot analysis, real-time polymerase chain reaction, enzyme-linked immunosorbent assay and immunofluorescence were used to measure the levels and distribution of the indicated indicators within cells and tissues. Reactive oxygen species and autophagic flux alterations were detected using specific probes.

Results

BRD3308, which is a inhibitor of histone deacetylase 3, improved lung tissue damage, inflammatory infiltration and edema in ALI by inhibiting Nod-like receptor protein3-mediated pyroptosis in macrophages. By upregulating autophagy, BRD3308 improved the disruption of redox balance in macrophages and reduced the accumulation of reactive oxygen species. Mechanistically, BRD3308 inhibited histone deacetylase 3 activity by binding to it and altering its conformation. Following histone deacetylase 3 inhibition, acetylation of H3K27 was significantly increased. Moreover, the increase in H3K27Ac led to the upregulation of autophagy-related gene 5, a key component of autophagosomes, thereby activating autophagy.

Conclusions

BRD3308 inhibits oxidative stress and pyroptosis in macrophages by modulating histone acetylation, thereby preventing sepsis-induced ALI. The present study provides a potential strategy and theoretical basis for the clinical treatment of sepsis-induced ALI.

Role of gasdermin D in inflammatory diseases: from mechanism to therapeutics

Inflammatory diseases compromise a clinically common and diverse group of conditions, causing detrimental effects on body functions. Gasdermins (GSDM) are pore-forming proteins, playing pivotal roles in modulating inflammation. Belonging to the GSDM family, gasdermin D (GSDMD) actively mediates the pathogenesis of inflammatory diseases by mechanistically regulating different forms of cell death, particularly pyroptosis, and cytokine release, in an inflammasome-dependent manner. Aberrant activation of GSDMD in different types of cells, such as immune cells, cardiovascular cells, pancreatic cells and hepatocytes, critically contributes to the persistent inflammation in different tissues and organs. The contributory role of GSDMD has been implicated in diabetes mellitus, liver diseases, cardiovascular diseases, neurodegenerative diseases, and inflammatory bowel disease (IBD). Clinically, alterations in GSDMD levels are potentially indicative to the occurrence and severity of diseases. GSDMD inhibition might represent an attractive therapeutic direction to counteract the progression of inflammatory diseases, whereas a number of GSDMD inhibitors have been shown to restrain GSDMD-mediated pyroptosis through different mechanisms. This review discusses the current understanding and future perspectives on the role of GSDMD in the development of inflammatory diseases, as well as the clinical insights of GSDMD alterations, and therapeutic potential of GSDMD inhibitors against inflammatory diseases. Further investigation on the comprehensive role of GSDM shall deepen our understanding towards inflammation, opening up more diagnostic and therapeutic opportunities against inflammatory diseases.

Dichloroacetate Prevents Sepsis Associated Encephalopathy by Inhibiting Microglia Pyroptosis through PDK4/NLRP3

Dichloroacetate (DCA), a pyruvate dehydrogenase kinase inhibitor, is often used to treat lactic acidosis and malignant tumors. Increasing studies have shown that DCA has neuroprotective effects. Here, we explored the role and mechanism of DCA in Sepsis associated encephalopathy (SAE). Single-cell analysis was used to determine the important role of PDK4 in SAE and identify the cell type. GO and GSEA analysis were used to determine the correlation between DCA and pyroptosis. Through LPS + ATP stimulation, a microglia pyroptosis model was established to observe the expression level of intracellular pyroptosis-related proteins under DCA intervention, and further detect the changes in intracellular ROS and JC-1. Additionally, a co-culture environment of microglia and neuron was simply constructed to evaluate the effect of DCA on activated microglia-mediated neuronal apoptosis. Finally, Novel object recognition test and the Morris water maze were used to explore the effect of DCA on cognitive function in mice from different groups after intervention. Based on the above experiments, this study concludes that DCA can improve the ratio of peripheral and central M1 macrophages, inhibit NLRP3-mediated pyroptosis through ROS and mitochondrial membrane potential (MMP). DCA can reduce neuron death caused by SAE and improve cognitive function in LPS mice. In SAE, DCA may be a potential candidate drug for the treatment of microglia-mediated neuroinflammation.

Mitochondria: a breakthrough in combating rheumatoid arthritis

As a chronic autoimmune disease with complex aetiology, rheumatoid arthritis (RA) has been demonstrated to be associated with mitochondrial dysfunction since mitochondrial dysfunction can affect the survival, activation, and differentiation of immune and non-immune cells involved in the pathogenesis of RA. Nevertheless, the mechanism behind mitochondrial dysfunction in RA remains uncertain. Accordingly, this review addresses the possible role and mechanisms of mitochondrial dysfunction in RA and discusses the potential and challenges of mitochondria as a potential therapeutic strategy for RA, thereby providing a breakthrough point in the prevention and treatment of RA.

Oxidative cell death in cancer: mechanisms and therapeutic opportunities

Reactive oxygen species (ROS) are highly reactive oxygen-containing molecules generated as natural byproducts during cellular processes, including metabolism. Under normal conditions, ROS play crucial roles in diverse cellular functions, including cell signaling and immune responses. However, a disturbance in the balance between ROS production and cellular antioxidant defenses can lead to an excessive ROS buildup, causing oxidative stress. This stress damages essential cellular components, including lipids, proteins, and DNA, potentially culminating in oxidative cell death. This form of cell death can take various forms, such as ferroptosis, apoptosis, necroptosis, pyroptosis, paraptosis, parthanatos, and oxeiptosis, each displaying distinct genetic, biochemical, and signaling characteristics. The investigation of oxidative cell death holds promise for the development of pharmacological agents that are used to prevent tumorigenesis or treat established cancer. Specifically, targeting key antioxidant proteins, such as SLC7A11, GCLC, GPX4, TXN, and TXNRD, represents an emerging approach for inducing oxidative cell death in cancer cells. This review provides a comprehensive summary of recent progress, opportunities, and challenges in targeting oxidative cell death for cancer therapy.

Melatonin Rescues Influenza A Virus-Induced Cellular Energy Exhaustion via OMA1-OPA1-S in Acute Exacerbation of COPD

Although rapid progression and a poor prognosis in influenza A virus (IAV) infection-induced acute exacerbation of chronic obstructive pulmonary disease (AECOPD) are frequently associated with metabolic energy disorders, the underlying mechanisms and rescue strategies remain unknown. We herein demonstrated that the level of resting energy expenditure increased significantly in IAV-induced AECOPD patients and that cellular energy exhaustion emerged earlier and more significantly in IAV-infected primary COPD bronchial epithelial (pDHBE) cells. The differentially expressed genes were enriched in the oxidative phosphorylation (OXPHOS) pathway; additionally, we consistently uncovered much earlier ATP exhaustion, more severe mitochondrial structural destruction and dysfunction, and OXPHOS impairment in IAV-inoculated pDHBE cells, and these changes were rescued by melatonin. The level of OMA1-dependent cleavage of OPA1 in the mitochondrial inner membrane and the shift in energy metabolism from OXPHOS to glycolysis were significantly increased in IAV-infected pDHBE cells; however, these changes were rescued by OMA1-siRNA or melatonin further treatment. Collectively, our data revealed that melatonin rescued IAV-induced cellular energy exhaustion via OMA1-OPA1-S to improve the clinical prognosis in COPD. This treatment may serve as a potential therapeutic agent for patients in which AECOPD is induced by IAV.

Oxidative Stress-Mediated Programmed Cell Death: a Potential Therapy Target for Atherosclerosis

Nowadays, as a type of orderly and active death determined by genes, programmed cell death (PCD), including apoptosis, pyroptosis, ferroptosis, and necroptosis, has attracted much attention owing to its participation in numerous chronic cardiovascular diseases, especially atherosclerosis (AS), a canonical chronic inflammatory disease featured by lipid metabolism disturbance. Abundant researches have reported that PCD under distinct internal conditions fulfills different roles of atherosclerotic pathological processes, including lipid core expansion, leukocyte adhesion, and infiltration. Noteworthy, emerging evidence recently has also suggested that oxidative stress (OS), an imbalance of antioxidants and oxygen free radicals, has the potential to mediate PCD occurrence via multiple ways, including oxidization and deubiquitination. Interestingly, more recently, several studies have proposed that the mediating mechanisms could effect on the atherosclerotic initiation and progression significantly from variable aspects, so it is of great clinical importance to clarify how OS-mediated PCD and AS interact. Herein, with the aim of summarizing potential and sufficient atherosclerotic therapy targets, we seek to provide extensive analysis of the specific regulatory mechanisms of PCD mediated by OS and their multifaceted effects on the entire pathological atherosclerotic progression.

Targeting ROS in cancer: rationale and strategies

Reactive oxygen species (ROS) in biological systems are transient but essential molecules that are generated and eliminated by a complex set of delicately balanced molecular machineries. Disruption of redox homeostasis has been associated with various human diseases, especially cancer, in which increased ROS levels are thought to have a major role in tumour development and progression. As such, modulation of cellular redox status by targeting ROS and their regulatory machineries is considered a promising therapeutic strategy for cancer treatment. Recently, there has been major progress in this field, including the discovery of novel redox signalling pathways that affect the metabolism of tumour cells as well as immune cells in the tumour microenvironment, and the intriguing ROS regulation of biomolecular phase separation. Progress has also been made in exploring redox regulation in cancer stem cells, the role of ROS in determining cell fate and new anticancer agents that target ROS. This Review discusses these research developments and their implications for cancer therapy and drug discovery, as well as emerging concepts, paradoxes and future perspectives.

Esaxerenone Attenuates Aldosterone-Induced Mitochondrial Damage-Mediated Pyroptosis in Mouse Aorta and Rat Vascular Smooth Muscle Cells

BACKGROUND

Vascular smooth muscle cell (VSMC) injury caused by the inflammatory response plays a key role in cardiovascular disease (CVD), and the vasoprotective effects of mineralocorticoid receptor blockers (MRBs) support the role of mineralocorticoid receptor (MR) activation.

METHODS

C57BL/6 mice and VSMCs isolated from rats were treated with aldosterone and esaxerenone. Caspase-1, GSDMD-N, IL-1β, and NR3C2 expression and DNA damage in aortic VSMCs were detected using immunohistochemistry, Western blotting, and TUNEL staining. Mitochondrial changes were detected by transmission electron microscopy (TEM). Reactive oxygen species (ROS), MitoTracker, JC-I, mitochondrial respiratory chain complexes I-V, and NR3C2 were detected using immunofluorescence and flow cytometry. Pyroptosis was detected with scanning electron microscopy (SEM).

RESULTS

After aldosterone treatment, the number of TUNEL-positive cells increased significantly, and the expression of caspase-1, GSDMD-N, and IL-1β increased. TEM revealed mitochondrial damage, and SEM revealed specific pyroptotic changes, such as cell membrane pore changes and cytoplasmic extravasation. Increased ROS levels and nuclear translocation of NR3C2 were also observed. These pyroptosis-related changes were reversed by esaxerenone.

CONCLUSIONS

Aldosterone activates the MR and mediates mitochondrial damage, thereby inducing pyroptosis in VSMCs via the NLRP3/caspase-1 pathway. Esaxerenone inhibits MR activation and reduces mitochondrial damage and oxidative stress, thereby inhibiting pyroptosis.

Reactive oxygen species in hypertension

Hypertension is a leading risk factor for stroke, heart disease and chronic kidney disease. Multiple interacting factors and organ systems increase blood pressure and cause target-organ damage. Among the many molecular elements involved in the development of hypertension are reactive oxygen species (ROS), which influence cellular processes in systems that contribute to blood pressure elevation (such as the cardiovascular, renal, immune and central nervous systems, or the renin-angiotensin-aldosterone system). Dysregulated ROS production (oxidative stress) is a hallmark of hypertension in humans and experimental models. Of the many ROS-generating enzymes, NADPH oxidases are the most important in the development of hypertension. At the cellular level, ROS influence signalling pathways that define cell fate and function. Oxidative stress promotes aberrant redox signalling and cell injury, causing endothelial dysfunction, vascular damage, cardiovascular remodelling, inflammation and renal injury, which are all important in both the causes and consequences of hypertension. ROS scavengers reduce blood pressure in almost all experimental models of hypertension; however, clinical trials of antioxidants have yielded mixed results. In this Review, we highlight the latest advances in the understanding of the role and the clinical implications of ROS in hypertension. We focus on cellular sources of ROS, molecular mechanisms of oxidative stress and alterations in redox signalling in organ systems, and their contributions to hypertension.

Icariin suppresses nephrotic syndrome by inhibiting pyroptosis and epithelial-to-mesenchymal transition

CONTEXT

Nephrotic syndrome(NS) has emerged as a worldwide public health problem. Renal fibrosis is the most common pathological change from NS to end-stage renal failure, seriously affecting the prognosis of renal disease. Although tremendous efforts have been made to treat NS, specific drug therapies to delay the progression of NS toward end-stage renal failure are limited. Epimedium is generally used to treat kidney disease in traditional Chinese medicine. Icariin is a principal active component of Epimedium.

METHODS

We used Sprague Dawley rats to establish NS models by injecting doxorubicin through the tail vein. Then icariin and prednisone were intragastric administration. Renal function was examined by an automatic biochemical analyzer. Pathology of the kidney was detected by Hematoxylin-Eosin and Masson staining respectively. Furthermore, RT-PCR, Enzyme-Linked Immunosorbent Assay, Immunohistochemistry, Western Blot and Terminal-deoxynucleotidyl Transferase Mediated Nick End Labeling staining were employed to detect the proteins related to pyroptosis and EMT. HK-2 cells exposed to doxorubicin were treated with icariin, and cell viability was assessed using the MTT. EMT was assessed using Enzyme-Linked Immunosorbent Assay and Western Blot.

RESULTS

The study showed that icariin significantly improved renal function and renal fibrosis in rats. In addition, icariin effectively decreased NOD-like receptor thermal protein domain associated protein 3,Caspase-1, Gasdermin D, Ly6C, and interleukin (IL)-1β. Notably, treatment with icariin also inhibited the levels of TGF-β, α-SMA and E-cadherin.

DISCUSSION AND CONCLUSIONS

It is confirmed that icariin can improve renal function and alleviate renal fibrosis by inhibiting pyroptosis and the mechanism may be related to epithelial-to-mesenchymal transition. Icariin treatment might be recommended as a new approach for NS.

Glaesserella parasuis serotype 5 induces pyroptosis via the RIG-I/MAVS/NLRP3 pathway in swine tracheal epithelial cells

Glaesserella parasuis (G. parasuis) is a common Gram-negative commensal bacterium in the upper respiratory tract of swine that can cause Glässer's disease under stress conditions. Pyroptosis is an important immune defence mechanism of the body that plays a crucial role in clearing pathogen infections and endogenous danger signals. This study aimed to investigate the mechanism of G. parasuis serotype 5 SQ (GPS5-SQ)-induced pyroptosis in swine tracheal epithelial cells (STECs). The results of the present study demonstrated that GPS5-SQ infection induces pyroptosis in STECs by enhancing the protein level of the N-terminal domain of gasdermin D (GSDMD-N) and activating the NOD-like receptor protein 3 (NLRP3) inflammasome. Furthermore, the levels of pyroptosis-related proteins, including GSDMD-N and cleaved caspase-1 were considerably decreased in STECs after the knockdown of retinoic acid inducible gene-I (RIG-I) and mitochondrial antiviral signaling protein (MAVS). These results indicated that GPS5-SQ might trigger pyroptosis through the activation of the RIG-I/MAVS/NLRP3 signaling pathway. More importantly, the reactive oxygen species (ROS) scavenger N-acetylcysteine (NAC) repressed the activation of the RIG-I/MAVS/NLRP3 signaling and rescued the decrease in Occludin and zonula occludens-1 (ZO-1) after GPS5-SQ infection. Overall, our findings show that GPS5-SQ can activate RIG-I/MAVS/NLRP3 signaling and destroy the integrity of the epithelial barrier by inducing ROS generation in STECs, shedding new light on G. parasuis pathogenesis.

Diallyl trisulfide induces pyroptosis and impairs lung CSC-like properties by activating the ROS/Caspase 1 signaling pathway

Lung cancer stem cells (CSCs) drive continuous cancer growth and metastatic dissemination; thus, there is an urgent requirement to acquire effective therapeutic strategies for targeting lung CSCs. Diallyl trisulfide (DATS), a garlic organosulfide, possesses suppressive potential in lung cancer; however, its underlying mechanism is still unclear. In this study, we identified DATS as a pyroptosis inducer in lung cancer cells. DATS-treated A549 and H460 cells exhibited pyroptotic cell death, with characteristic large bubbles appearing on their plasma membrane and LDH release. DATS induced cell death, arrested the cell cycle at the G2/M phase, and inhibited colony formation in lung cancer cells. Meanwhile, we found that DATS significantly suppressed the malignant features by impairing lung CSC-like properties, including sphere formation ability, CD133 positive cell number, and lung CSCs marker expression. Mechanistically, DATS induced cell pyroptosis via increasing the expression of NLRP3, ASC, Pro Caspase 1, Cleaved Caspase 1, GSDMD, GSDMD-N, and IL-1β. The verification experiments showed that the effects of DATS on pyroptosis and lung CSC-like properties were weakened after Caspase 1 inhibitor VX-765 treatment, indicating that DATS activated NLRP3 inflammasome-mediated pyroptosis by targeting Caspase 1 in lung cancer cells. Moreover, DATS increased ROS overproduction and mitochondrial dysfunction, which contributed to DATS-induced pyroptosis of lung cancer cells. NAC treatment reversed the effects of DATS on pyroptosis and CSC-like properties. In vivo experiment further confirmed that DATS restrained tumor growth. Together, our results suggest that DATS promotes pyroptosis and impairs lung CSC-like properties by activating ROS/Caspase 1 signaling pathway, thereby retarding lung cancer progression.

Decoding Organelle Interactions: Unveiling Molecular Mechanisms and Disease Therapies

Organelles, substructures in the cytoplasm with specific morphological structures and functions, interact with each other via membrane fusion, membrane transport, and protein interactions, collectively termed organelle interaction. Organelle interaction is a complex biological process involving the interaction and regulation of several organelles, including the interaction between mitochondria-endoplasmic reticulum, endoplasmic reticulum-Golgi, mitochondria-lysosomes, and endoplasmic reticulum-peroxisomes. This interaction enables intracellular substance transport, metabolism, and signal transmission, and is closely related to the occurrence, development, and treatment of many diseases, such as cancer, neurodegenerative diseases, and metabolic diseases. Herein, the mechanisms and regulation of organelle interactions are reviewed, which are critical for understanding basic principles of cell biology and disease development mechanisms. The findings will help to facilitate the development of novel strategies for disease prevention, diagnosis, and treatment opportunities.

Nasal mucosa-derived mesenchymal stem cells prolonged the survival of septic rats by protecting macrophages from pyroptosis

Sepsis is characterized by an exacerbated inflammatory response, driven by the overproduction of cytokines, a phenomenon known as a cytokine storm. This condition is further compounded by the extensive infiltration of M1 macrophages and the pyroptosis of these cells, leading to immune paralysis. To counteract this, we sought to transition M1 macrophages into the M2 phenotype and safeguard them from pyroptosis. For this purpose, we employed ectodermal mesenchymal stem cells (EMSCs) sourced from the nasal mucosa to examine their impact on both macrophages and septic animal models. The co-culture protocol involving LPS-stimulated rat bone marrow macrophages and EMSCs was employed to examine the paracrine influence of EMSCs on macrophages. The intravenous administration of EMSCs was utilized to observe the enhancement in the survival rate of septic rat models and the protection of associated organs. The findings indicated that EMSCs facilitated M2 polarization of macrophages, which were stimulated by LPS, and significantly diminished levels of pro-inflammatory cytokines and NLRP3. Furthermore, EMSCs notably restored the mitochondrial membrane potential (MMP) of macrophages through paracrine action, eliminated excess reactive oxygen species (ROS), and inhibited macrophage pyroptosis. Additionally, the systemic integration of EMSCs substantially reduced injuries to multiple organs and preserved the fundamental functions of the heart, liver, and kidney in CLP rats, thereby extending their survival.

A detective story of intermittent fasting effect on immunity

Intermittent fasting (IF) refers to periodic fasting routines, that caloric intake is minimized not by meal portion size reduction but by intermittently eliminating ingestion of one or several consecutive meals. IF can instigate comprehensive and multifaceted alterations in energy metabolism, these metabolic channels may aboundingly function as primordial mechanisms that interface with the immune system, instigating intricate immune transformations. This review delivers a comprehensive understanding of IF, paying particular attention to its influence on the immune system, thus seeking to bridge these two research domains. We explore how IF effects lipid metabolism, hormonal levels, circadian rhythm, autophagy, oxidative stress, gut microbiota, and intestinal barrier integrity, and conjecture about the mechanisms orchestrating the intersect between these factors and the immune system. Moreover, the review includes research findings on the implications of IF on the immune system and patients burdened with autoimmune diseases.

Tetrahedral Framework Nucleic Acid-Based Delivery of Astaxanthin Suppresses Chondrocyte Pyroptosis and Modulates Oxidative Stress for the Treatment of Osteoarthritis

Worldwide, osteoarthritis (OA) is regarded as the most widespread, distressing, and limiting chronic disease that affects degenerative joints. Currently, there is no treatment available to modify the progression of OA. The pathogenesis of OA is significantly linked with oxidative stress and pyroptosis. Astaxanthin (Ast) is a natural ketocarotenoid pigment with potent antioxidant activity and is shown to effectively alleviate cartilage damage in OA. However, its bioavailability is greatly limited due to poor water solubility, high sensitivity to light, temperature, and pH. In this study, Ast-loaded tetrahedral framework nucleic acids (tFNAs) or tFNA/Ast complexes (TAC) for Ast delivery are developed. Compared with free Ast and tFNA alone, TAC exhibits improved drug stability and cellular uptake. Most importantly, TAC effectively protects chondrocytes against oxidative stress-induced pyroptosis while promoting extracellular matrix anabolism by chondrocytes, and ultimately alleviates cartilage damage in a mouse destabilization of the medial meniscus (DMM) model. Thus, TAC holds great promise for the treatment of OA patients.

Neutrophil extracellular traps induce pyroptosis of pulmonary microvascular endothelial cells by activating the NLRP3 inflammasome

Excessive formation of neutrophil extracellular traps (NETs) may lead to myositis-related interstitial lung disease (ILD). There is evidence that NETs can directly injure vascular endothelial cells and play a pathogenic role in the inflammatory exudation of ILD. However, the specific mechanism is unclear. This study aimed to investigate the specific mechanism underlying NET-induced injury to human pulmonary microvascular endothelial cells (HPMECs). HPMECs were stimulated with NETs (200 ng/ml) in vitro. Cell death was detected by propidium iodide staining. The morphological changes of the cells were observed by transmission electron microscopy (TEM). Pyroptosis markers were detected by western blot, immunofluorescence, and quantitative real-time polymerase chain reaction, and the related inflammatory factor Interleukin-1β (IL-1β) was verified by enzyme-linked immunosorbent assay (ELISA). Compared with the control group, HPMECs mortality increased after NET stimulation, and the number of pyroptosis vacuoles in HPMECs was further observed by TEM. The pulmonary microvascular endothelial cells (PMECs) of the experimental autoimmune myositis mouse model also showed a trend of pyroptosis in vivo. Cell experiment further confirmed the significantly high expression of the NLRP3 inflammasome and pyroptosis-related markers, including GSDMD and inflammatory factor IL-1β. Pretreated with the NLRP3 inhibitor MCC950, the activation of NLRP3 inflammasome and pyroptosis of HPMECs were effectively inhibited. Our study confirmed that NETs promote pulmonary microvascular endothelial pyroptosis by activating the NLRP3 inflammasome, suggesting that NETs-induced pyroptosis of PMECs may be a potential pathogenic mechanism of inflammatory exudation in ILD.

FeSA‐Ir/Metallene Nanozymes Induce Sequential Ferroptosis‐Pyroptosis for Multi‐Immunogenic Responses Against Lung Metastasis

For cancer metastasis inhibition, the combining of nanozymes with immune checkpoint blockade (ICB) therapy remains the major challenge in controllable reactive oxygen species (ROS) generation for creating effective immunogenicity. Herein, new nanozymes with light-controlled ROS production in terms of quantity and variety are developed by conjugating supramolecular-wrapped Fe single atom on iridium metallene with lattice-strained nanoislands (FeSA-Ir@PF NSs). The Fenton-like catalysis of FeSA-Ir@PF NSs effectively produced •OH radicals in dark, which induced ferroptosis and apoptosis of cancer cells. While under second near-infrared (NIR-II) light irradiation, FeSA-Ir@PF NSs showed ultrahigh photothermal conversion efficiency (𝜂, 75.29%), cooperative robust •OH generation, photocatalytic O2 and 1O2 generation, and caused significant pyroptosis of cancer cells. The controllable ROS generation, sequential cancer cells ferroptosis and pyroptosis, led 99.1% primary tumor inhibition and multi-immunogenic responses in vivo. Most importantly, the inhibition of cancer lung metastasis is completely achieved by FeSA-Ir@PF NSs with immune checkpoint inhibitors, as demonstrated in different mice lung metastasis models, including circulating tumor cells (CTCs) model. This work provided new inspiration for developing nanozymes for cancer treatments and metastasis inhibition.

Macrophage Perspectives in Liver Diseases: Programmed Death, Related Biomarkers, and Targeted Therapy

Macrophages, as important immune cells of the organism, are involved in maintaining intrahepatic microenvironmental homeostasis and can undergo rapid phenotypic changes in the injured or recovering liver. In recent years, the crucial role of macrophage-programmed cell death in the development and regression of liver diseases has become a research hotspot. Moreover, macrophage-targeted therapeutic strategies are emerging in both preclinical and clinical studies. Given the macrophages' vital role in complex organismal environments, there is tremendous academic interest in developing novel therapeutic strategies that target these cells. This review provides an overview of the characteristics and interactions between macrophage polarization, programmed cell death, related biomarkers, and macrophage-targeted therapies. It aims to deepen the understanding of macrophage immunomodulation and molecular mechanisms and to provide a basis for the treatment of macrophage-associated liver diseases.

Polyhexamethylene guanidine phosphate induces pyroptosis via reactive oxygen species-regulated mitochondrial dysfunction in bronchial epithelial cells

Pyroptosis is a form of programmed cell death characterized by gasdermin (GSDM)-mediated pore formation in the cell membrane, resulting in the release of pro-inflammatory cytokines and cellular lysis. Increasing evidence has shown that pyroptosis is responsible for the progression of various pulmonary disorders. The inhalation of polyhexamethylene guanidine (PHMG) causes severe lung inflammation and pulmonary toxicity; however, the underlying mechanisms are unknown. Therefore, in this study, we investigate the role of pyroptosis in PHMG-induced pulmonary toxicity. We exposed bronchial epithelial cells, BEAS-2B, to PHMG phosphate (PHMG-p) and evaluated cell death type, reactive oxygen species (ROS) levels, and relative expression levels of pyroptosis-related proteins. Our data revealed that PHMG-p reduced viability and induced morphological alterations in BEAS-2B cells. Exposure to PHMG-p induced excessive accumulation of mitochondrial ROS (mtROS) in BEAS-2B cells. PHMG-p activated caspase-dependent apoptosis as well as NLRP3/caspase-1/GSDMD-mediated- and caspase-3/GSDME-mediated pyroptosis through mitochondrial oxidative stress in BEAS-2B cells. Notably, PHMG-p reduced mitochondrial respiratory function and induced the translocation of Bax and cleaved GSDM into the mitochondria, leading to mitochondrial dysfunction. Our results enhanced our understanding of PHMG-p-induced lung toxicity by demonstrating that PHMG-p induces pyroptosis via mtROS-induced mitochondrial dysfunction in bronchial epithelial cells.

Redox regulation of macrophages

Redox signaling, a mode of signal transduction that involves the transfer of electrons from a nucleophilic to electrophilic molecule, has emerged as an essential regulator of inflammatory macrophages. Redox reactions are driven by reactive oxygen/nitrogen species (ROS and RNS) and redox-sensitive metabolites such as fumarate and itaconate, which can post-translationally modify specific cysteine residues in target proteins. In the past decade our understanding of how ROS, RNS, and redox-sensitive metabolites control macrophage function has expanded dramatically. In this review, we discuss the latest evidence of how ROS, RNS, and metabolites regulate macrophage function and how this is dysregulated with disease. We highlight the key tools to assess redox signaling and important questions that remain.

Discovery of a mitochondrial G-quadruplex targeted fluorescent ligand via a slight variation on the near-infrared heptamethine cyanine scaffold

The heptamethine cyanine dyes are one kind of promising near-infrared (NIR) compounds, holding great potential in both diagnostic and therapeutic regions. Remolding such structures to realize detection of unclarified biotargets or interfering with them seems to be important in the field of chemical biology. In this study, we developed a fluorescent ligand (IR1) targeting mitochondrial G-quadruplexes (mitoG4s) by a slight variation on the typical NIR scaffold (IR780). This ligand could be applied for sensing mitoG4s by fluorescence, making it different from the unmodified dye whose fluorescence was quenched by mitoG4s. Then, IR1 was demonstrated to accumulate in the mitochondria through a mitochondrial membrane potential (MMP) dependent manner. Some of IR1 then bound to mitoG4s, causing mtDNA loss and mitochondrial dysfunction, which thereby triggered PANoptosis, including apoptosis, autophagy and pyroptosis. To the best of our knowledge, IR1 was the first NIR fluorescent ligand with emission centered at above 800 nm for mitoG4s, and the first example causing PANoptosis among the reported mitoG4-targeted ligands.

Modulating synovial macrophage pyroptosis and mitophagy interactions to mitigate osteoarthritis progression using functionalized nanoparticles

Synovial macrophages play an important role in the progression of osteoarthritis (OA). In this study, we noted that synovial macrophages can activate pyroptosis in a gasdermin d-dependent manner and produce reactive oxygen species (ROS), aberrantly activating the mammalian target of rapamycin complex 1 (mTORC1) pathway and matrix metalloproteinase-9 (MMP9) expression in synovial tissue samples collected from both patients with OA and collagen-induced osteoarthritis (CIOA) mouse model. To overcome this, we constructed rapamycin- (RAPA, a mTORC1 inhibitor) loaded mesoporous Prussian blue nanoparticles (MPB NPs, for catalyzing ROS) and modified the NPs with MMP9-targeted peptides (favor macrophage targeting) to develop RAPA@MPB-MMP9 NPs. The inherent enzyme-like activity and RAPA released from RAPA@MPB-MMP9 NPs synergistically impeded the pyroptosis of macrophages and the activation of the mTORC1 pathway. In particular, the NPs decreased pyroptosis-mediated ROS generation, thereby inhibiting cGAS-STING signaling pathway activation caused by the release of mitochondrial DNA. Moreover, the NPs promoted macrophage mitophagy to restore mitochondrial stability, alleviate pyroptosis-related inflammatory responses, and decrease senescent synoviocytes. After the as-prepared NPs were intra-articularly injected into the CIOA mouse model, they efficiently attenuated synovial macrophage pyroptosis and cartilage degradation. In conclusion, our study findings provide a novel therapeutic strategy for OA that modulates the pyroptosis and mitophagy of synovial macrophage by utilizing functionalized NPs. STATEMENT OF SIGNIFICANCE: Osteoarthritis (OA) presents a significant global challenge owing to its complex pathogenesis and finite treatment options. Synovial macrophages have emerged as key players in the progression of OA, managing inflammation and tissue destruction. In this study, we discovered a novel therapeutic strategy in which the pyroptosis and mitophagy of synovial macrophages are targeted to mitigate OA pathology. For this, we designed and prepared rapamycin-loaded mesoporous Prussian blue nanoparticles (RAPA@MPB-MMP9 NPs) to specifically target synovial macrophages and modulate their inflammatory responses. These NPs could efficiently suppress macrophage pyroptosis, diminish reactive oxygen species production, and promote mitophagy, thereby alleviating inflammation and protecting cartilage integrity. Our study findings not only clarify the intricate mechanisms underlying OA pathogenesis but also present a promising therapeutic approach for effectively managing OA by targeting dysregulation in synovial macrophages.

Xijiao Dihuang decoction combined with Yinqiao powder promotes autophagy-dependent ROS decrease to inhibit ROS/NLRP3/pyroptosis regulation axis in influenza virus infection

BACKGROUND

Influenza viral pneumonia is a common complication after influenza virus infection. Xijiao Dihuang Decoction combined with Yinqiao Powder (XDY) is effective on improving influenza viral pneumonia.

PURPOSE

This study further explores the anti-inflammatory mechanism of XDY in the treatment of influenza viral pneumonia.

STUDY DESIGN

The effects of XDY on inflammation, autophagy, NACHT-LRR-PYD-containing protein 3 (NLRP3) inflammasome and pyroptosis were assessed in the mice with influenza viral pneumonia. In addition, the mouse macrophage cell line (J774A.1) infected with influenza virus was adopted to decode the in vitro effects of XDY on autophagy, reactive oxygen species (ROS), NLRP3 inflammasome and pyroptosis. We analyzed the XDY-induced autophagy, especially the mitophagy-related ROS clearance, and the subsequent inhibition of ROS/NLRP3 inflammasome/pyroptosis signaling in the infected macrophages by different assays based on quantitative polymerase chain reaction, western blot, flow cytometry, immunofluorescence and enzyme-linked immunosorbent assay.

RESULTS

In vivo, XDY could effectively improve the lung inflammatory response in the mice with influenza virus pneumonia, due to an intact autophagy flux-promoting effect and the inhibiting roles on NLRP3 inflammasome and pyroptosis. Notably, in vitro, compared with the infected macrophages treated by the NLRP3 inflammasome agonist (Monosodium urate) or the mitochondrial-targeted antioxidant agent, the XDY-dependent treating could inhibit pyroptosis by negatively regulating the signaling axis of ROS/NLRP3 inflammasome/pyroptosis in the influenza virus-infected macrophages. More interestingly, XDY could promote an intact autophagy flux, inducing mitophagy eliminating the damaged mitochondria to reduce the intracellular ROS accumulation, and thus decrease the oxidative stress in the infected macrophages. Especially, the inhibitor of autophagy inition, 3-Methyladenine, could reverse the inhibitory effect of XDY on ROS-NLRP3 inflammasome-mediated pyroptosis, indicating an XDY-promoted mitophagy-dependent ROS scavenging.

CONCLUSION

XDY can promote an intact autophagy flux to eliminate damaged mitochondria, namely mitophagy, which reduces the intracellular ROS accumulation contributing to NLRP3 inflammasome activation, restricting pyroptosis and eventually alleviating the influenza virus-induced inflammatory lesions. The obtained results provide new insights into the mechanism of action of XDY in alleviating influenza virus pneumonia, especially the roles of XDY in anti-oxidation, anti-inflammation and anti-pyroptosis, with potential therapeutic targets for future application in integrative medicine.

Redox signaling in cell fate: Beyond damage

This review explores the nuanced role of reactive oxygen species (ROS) in cell fate, challenging the traditional view that equates ROS with cellular damage. Through significant technological advancements in detecting localized redox states and identifying oxidized cysteines, a paradigm shift has emerged: from ROS as merely damaging agents to crucial players in redox signaling. We delve into the intricacies of redox mechanisms, which, although confined, exert profound influences on cellular physiological responses. Our analysis extends to both the positive and negative impacts of these mechanisms on cell death processes, including uncontrolled and programmed pathways. By unraveling these complex interactions, we argue against the oversimplified notion of a 'stress response', advocating for a more nuanced understanding of redox signaling. This review underscores the importance of localized redox states in determining cell fate, highlighting the sophistication and subtlety of ROS functions beyond mere damage.

Post-translational control of NLRP3 inflammasome signaling

Inflammasomes serve as critical sensors for disruptions to cellular homeostasis, with inflammasome assembly leading to inflammatory caspase activation, gasdermin cleavage, and cytokine release. While the canonical pathways leading to priming, assembly, and pyroptosis are well characterized, recent work has begun to focus on the role of post-translational modifications (PTMs) in regulating inflammasome activity. A diverse array of PTMs, including phosphorylation, ubiquitination, SUMOylation, acetylation, and glycosylation, exert both activating and inhibitory influences on members of the inflammasome cascade through effects on protein-protein interactions, stability, and localization. Dysregulation of inflammasome activation is associated with a number of inflammatory diseases, and evidence is emerging that aberrant modification of inflammasome components contributes to this dysregulation. This review provides insight into PTMs within the NLRP3 inflammasome pathway and their functional consequences on the signaling cascade and highlights outstanding questions that remain regarding the complex web of signals at play.

Pyroptosis Signature Gene CHMP4B Regulates Microglia Pyroptosis by Inhibiting GSDMD in Alzheimer's Disease

In this study, we aimed to work through the key genes involved in the process of pyroptosis in Alzheimer's disease (AD) to identify potential biomarkers using bioinformatics technology and further explore the underlying molecular mechanisms. The transcriptome data of brain tissue in AD patients were screened from the GEO database, and pyroptosis-related genes were analyzed. The functions of differential genes were analyzed by enrichment analysis and protein-protein interaction. The diagnostic model was established using LASSO and logistic regression analysis, and the correlation of clinical data was analyzed. Based on single-cell analysis of brain tissues of patients with AD, immunofluorescence and western blotting were used to explore the key cells affected by the hub gene. After GSEA, qRT-PCR, western blotting, LDH, ROS, and JC-1 were used to investigate the potential mechanism of the hub gene on pyroptosis. A total of 15 pyroptosis differentially expressed genes were identified. A prediction model consisting of six genes was established by LASSO and logistic regression analysis, and the area under the curve was up to 0.81. As a hub gene, CHMP4B was negatively correlated with the severity of AD. CHMP4B expression was decreased in the hippocampal tissue of patients with AD and mice. Single-cell analysis showed that CHMP4B was downregulated in AD microglia. Overexpression of CHMP4B reduced the release of LDH and ROS and restored mitochondrial membrane potential, thereby alleviating the inflammatory response during microglial pyroptosis. In summary, CHMP4B as a hub gene provides a new strategy for the diagnosis and treatment of AD.

Immunomodulation by glucocorticoid-induced leucine zipper in macrophages: enhanced phagocytosis, protection from pyroptosis, and altered mitochondrial function

Glucocorticoids, which have long served as fundamental therapeutics for diverse inflammatory conditions, are still widely used, despite associated side effects limiting their long-term use. Among their key mediators is glucocorticoid-induced leucine zipper (GILZ), recognized for its anti-inflammatory and immunosuppressive properties. Here, we explore the immunomodulatory effects of GILZ in macrophages through transcriptomic analysis and functional assays. Bulk RNA sequencing of GILZ knockout and GILZ-overexpressing macrophages revealed significant alterations in gene expression profiles, particularly impacting pathways associated with the inflammatory response, phagocytosis, cell death, mitochondrial function, and extracellular structure organization activity. GILZ-overexpression enhances phagocytic and antibacterial activity against Salmonella typhimurium and Escherichia coli, potentially mediated by increased nitric oxide production. In addition, GILZ protects macrophages from pyroptotic cell death, as indicated by a reduced production of reactive oxygen species (ROS) in GILZ transgenic macrophages. In contrast, GILZ KO macrophages produced more ROS, suggesting a regulatory role of GILZ in ROS-dependent pathways. Additionally, GILZ overexpression leads to decreased mitochondrial respiration and heightened matrix metalloproteinase activity, suggesting its involvement in tissue remodeling processes. These findings underscore the multifaceted role of GILZ in modulating macrophage functions and its potential as a therapeutic target for inflammatory disorders, offering insights into the development of novel therapeutic strategies aimed at optimizing the benefits of glucocorticoid therapy while minimizing adverse effects.

Mitochondrial ROS participates in Porphyromonas gingivalis-induced pyroptosis in cementoblasts

This study aimed to investigate correlation between mitochondrial reactive oxygen species and Porphyromonas gingivalis in the process of cementoblast pyroptosis. Lactate dehydrogenase activity assay, enzyme-linked immunosorbent assay, western blotting and flow cytometry analysis were utilized to explore whether Porphyromonas gingivalis triggered pyroptosis in cementoblasts. Reactive oxygen species and mitochondrial reactive oxygen species were detected using flow cytometry and fluorescence staining. The effect of mitochondrial reactive oxygen species on the Porphyromonas gingivalis-induced pyroptosis of cementoblasts was assessed by Mito-Tempo, mitochondrion-targeted superoxide dismutase mimetic. Phosphorylation levels of p65 were measured by western blotting. SC75741, a nuclear factor-kappa B inhibitor, was added to block the nuclear factor-kappa B in the Porphyromonas gingivalis-infected cementoblasts. Porphyromonas gingivalis triggered pyroptosis of cementoblasts, and an elevation in reactive oxygen species generation in the mitochondria was observed. Inhibition of mitochondrial reactive oxygen species reduced pyroptosis and nuclear factor-kappa B signaling pathway mediated the pyroptotic cell death in Porphyromonas gingivalis-infected cementoblasts. Together, our findings demonstrate that mitochondrial reactive oxygen species increased by Porphyromonas gingivalis participated in the pyroptosis of cementoblasts. Targeting mitochondrial reactive oxygen species may offer therapeutic strategies for root surface remodeling or periodontal regeneration.

Multifaceted roles of Meg3 in cellular senescence and atherosclerosis

BACKGROUND AND AIMS

Long noncoding RNAs are involved in the pathogenesis of atherosclerosis. As long noncoding RNAs maternally expressed gene 3 (Meg3) prevents cellular senescence of hepatic vascular endothelium and obesity-induced insulin resistance, we decided to examine its role in cellular senescence and atherosclerosis.

METHODS AND RESULTS

By analyzing our data and human and mouse data from the Gene Expression Omnibus database, we found that Meg3 expression was reduced in humans and mice with cardiovascular disease, indicating its potential role in atherosclerosis. In Ldlr-/- mice fed a Western diet for 12 weeks, Meg3 silencing by chemically modified antisense oligonucleotides attenuated the formation of atherosclerotic lesions by 34.9% and 20.1% in male and female mice, respectively, revealed by en-face Oil Red O staining, which did not correlate with changes in plasma lipid profiles. Real-time quantitative PCR analysis of cellular senescence markers p21 and p16 revealed that Meg3 deficiency aggravates hepatic cellular senescence but not cellular senescence at aortic roots. Human Meg3 transgenic mice were generated to examine the role of Meg3 gain-of-function in the development of atherosclerosis induced by PCSK9 overexpression. Meg3 overexpression promotes atherosclerotic lesion formation by 29.2% in Meg3 knock-in mice independent of its effects on lipid profiles. Meg3 overexpression inhibits hepatic cellular senescence, while it promotes aortic cellular senescence likely by impairing mitochondrial function and delaying cell cycle progression.

CONCLUSIONS

Our data demonstrate that Meg3 promotes the formation of atherosclerotic lesions independent of its effects on plasma lipid profiles. In addition, Meg3 regulates cellular senescence in a tissue-specific manner during atherosclerosis. Thus, we demonstrated that Meg3 has multifaceted roles in cellular senescence and atherosclerosis.

1,7-diphenyl-4-hepten-3-one mitigates Alzheimer's-like pathology by inhibiting pyroptosis via activating the Nrf2 pathway

Pyroptosis-mediated neuron death plays a crucial role in neurodegenerative diseases, such as Alzheimer's disease (AD). However, the effect of 1,7-diphenyl-4-hepten-3-one (C1), a natural diarylheptanoid, on AD is unclear. Herein, we investigated the therapeutic effect of C1 on APP/PS1 mice and β-amyloid (Aβ)-induced HT22 cells. Our findings showed that C1 attenuated cognitive impairment and mitigated pathological damage in APP/PS1 mice. Furthermore, we found that C1 prevented oxidative stress damage and decreased the levels of pyroptosis-related proteins. In vitro experiments showed that C1 can improve the proliferation of Aβ-induced HT22 cells and decrease the levels of pyroptosis-related proteins in them. When Nrf2 was silenced, the positive effects of C1 in inhibiting pyroptosis were inhibited. Particularly, the production of pyroptosis-associated proteins, including NLRP3, GSDMD, and caspase-1, and the secretion of pro-inflammatory molecules, including IL-1 and IL-18, were increased. Altogether, these findings indicate that C1 can mitigate AD-like pathology via the inhibition of pyroptosis by activating the Nrf2 pathway. We believe that this study can provide alternative strategies for the prevention and treatment of AD.

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.

Revolutionizing breast cancer treatment: Harnessing the related mechanisms and drugs for regulated cell death (Review)

Breast cancer arises from the malignant transformation of mammary epithelial cells under the influence of various carcinogenic factors, leading to a gradual increase in its prevalence. This disease has become the leading cause of mortality among female malignancies, posing a significant threat to the health of women. The timely identification of breast cancer remains challenging, often resulting in diagnosis at the advanced stages of the disease. Conventional therapeutic approaches, such as surgical excision, chemotherapy and radiotherapy, exhibit limited efficacy in controlling the progression and metastasis of the disease. Regulated cell death (RCD), a process essential for physiological tissue cell renewal, occurs within the body independently of external influences. In the context of cancer, research on RCD primarily focuses on cuproptosis, ferroptosis and pyroptosis. Mounting evidence suggests a marked association between these specific forms of RCD, and the onset and progression of breast cancer. For example, a cuproptosis vector can effectively bind copper ions to induce cuproptosis in breast cancer cells, thereby hindering their proliferation. Additionally, the expression of ferroptosis‑related genes can enhance the sensitivity of breast cancer cells to chemotherapy. Likewise, pyroptosis‑related proteins not only participate in pyroptosis, but also regulate the tumor microenvironment, ultimately leading to the death of breast cancer cells. The present review discusses the unique regulatory mechanisms of cuproptosis, ferroptosis and pyroptosis in breast cancer, and the mechanisms through which they are affected by conventional cancer drugs. Furthermore, it provides a comprehensive overview of the significance of these forms of RCD in modulating the efficacy of chemotherapy and highlights their shared characteristics. This knowledge may provide novel avenues for both clinical interventions and fundamental research in the context of breast cancer.

Mitochondrial (mt)DNA-cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling promotes pyroptosis of macrophages via interferon regulatory factor (IRF)7/IRF3 activation to aggravate lung injury during severe acute pancreatitis

BACKGROUND

Macrophage proinflammatory activation contributes to the pathology of severe acute pancreatitis (SAP) and, simultaneously, macrophage functional changes, and increased pyroptosis/necrosis can further exacerbate the cellular immune suppression during the process of SAP, where cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) plays an important role. However, the function and mechanism of cGAS-STING in SAP-induced lung injury (LI) remains unknown.

METHODS

Lipopolysaccharide (LPS) was combined with caerulein-induced SAP in wild type, cGAS -/- and sting -/- mice. Primary macrophages were extracted via bronchoalveolar lavage and peritoneal lavage. Ana-1 cells were pretreated with LPS and stimulated with nigericin sodium salt to induce pyroptosis in vitro.

RESULTS

SAP triggered NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome activation-mediated pyroptosis of alveolar and peritoneal macrophages in mouse model. Knockout of cGAS/STING could ameliorate NLRP3 activation and macrophage pyroptosis. In addition, mitochondrial (mt)DNA released from damaged mitochondria further induced macrophage STING activation in a cGAS- and dose-dependent manner. Upregulated STING signal can promote NLRP3 inflammasome-mediated macrophage pyroptosis and increase serum interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α levels and, thus, exacerbate SAP-associated LI (SAP-ALI). Downstream molecules of STING, IRF7, and IRF3 connect the mtDNA-cGAS-STING axis and the NLRP3-pyroptosis axis.

CONCLUSIONS

Negative regulation of any molecule in the mtDNA-cGAS-STING-IRF7/IRF3 pathway can affect the activation of NLRP3 inflammasomes, thereby reducing macrophage pyroptosis and improving SAP-ALI in mouse model.

New insights into Gasdermin D pore formation

Gasdermin D (GSDMD) is a pore-forming protein that perforates the plasma membrane (PM) during pyroptosis, a pro-inflammatory form of cell death, to induce the unconventional secretion of inflammatory cytokines and, ultimately, cell lysis. GSDMD is activated by protease-mediated cleavage of its active N-terminal domain from the autoinhibitory C-terminal domain. Inflammatory caspase-1, -4/5 are the main activators of GSDMD via either the canonical or non-canonical pathways of inflammasome activation, but under certain stimuli, caspase-8 and other proteases can also activate GSDMD. Activated GSDMD can oligomerize and assemble into various nanostructures of different sizes and shapes that perforate cellular membranes, suggesting plasticity in pore formation. Although the exact mechanism of pore formation has not yet been deciphered, cysteine residues are emerging as crucial modulators of the oligomerization process. GSDMD pores and thus the outcome of pyroptosis can be modulated by various regulatory mechanisms. These include availability of activated GSDMD at the PM, control of the number of GSDMD pores by PM repair mechanisms, modulation of the lipid environment and post-translational modifications. Here, we review the latest findings on the mechanisms that induce GSDMD to form membrane pores and how they can be tightly regulated for cell content release and cell fate modulation.

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.

ARC@DPBNPs suppress LPS-induced acute lung injury via inhibiting macrophage pyroptosis and M1 polarization by ERK pathway in mice

AIM OF THE STUDY

Exploring the protective effect of ARC@DPBNP on lipopolysaccharides (LPS)-induced ALI and its underlying mechanism.

MATERIALS AND METHODS

ALI model was established by intransally administrating LPS (4 mg/kg) into C57BL/6 mice. The suppression effects of ALI was first compared between ARC (intragastric administrated, with doses ranging from 10 to 80 mg/kg) and ARC@BPBNPs (intratracheally administrated, with doses ranging from 1 to 4 mg/kg). Changes in lung histology post intratracheal intervention of 3 mg/kg ARC@DPBNPs were detected. The expression of pyrotosis pathway-related proteins in lungs as well as in RAW264.7 cells was detected by western blotting. The ASC expression in lung macrophages was examined using immune-fluorescent staining. The polarization of RAW264.7 cells and lung macrophages were detected by flow cytometry. The network pharmacology was constructed by Cytoscape, and the molecular docking was perfomed by AutoDock Vina.

RESULTS

Docking predicted the high affinity of ARC to MAPK1 (ERK2). HE staining showed that ARC@DPBNPs attenuated LPS-induced ALI at a remarkably lower dose than ARC. The improved histopathological changes, lung W/D weight ratio, and decreased of inflammatory factor levels in lung collectively demonstrated the alleviation effects of ARC@DPBNPs. Compared with the LPS group, ARC@DPBNPs down-regulated the ERK pathway, resulted in a suppression of the macrophage pyroptosis and M1 polarization. This suppression effects could be removed by the ERK activator Ro 67-7476.

CONCLUSION

ARC@DPBNPs attenuated ALI by suppressing LPS-induced macrophage pyroptosis and polarization, probably through down-regulation of the ERK pathway.

The gasdermin family: emerging therapeutic targets in diseases

The gasdermin (GSDM) family has garnered significant attention for its pivotal role in immunity and disease as a key player in pyroptosis. This recently characterized class of pore-forming effector proteins is pivotal in orchestrating processes such as membrane permeabilization, pyroptosis, and the follow-up inflammatory response, which are crucial self-defense mechanisms against irritants and infections. GSDMs have been implicated in a range of diseases including, but not limited to, sepsis, viral infections, and cancer, either through involvement in pyroptosis or independently of this process. The regulation of GSDM-mediated pyroptosis is gaining recognition as a promising therapeutic strategy for the treatment of various diseases. Current strategies for inhibiting GSDMD primarily involve binding to GSDMD, blocking GSDMD cleavage or inhibiting GSDMD-N-terminal (NT) oligomerization, albeit with some off-target effects. In this review, we delve into the cutting-edge understanding of the interplay between GSDMs and pyroptosis, elucidate the activation mechanisms of GSDMs, explore their associations with a range of diseases, and discuss recent advancements and potential strategies for developing GSDMD inhibitors.

Involution of brown adipose tissue through a Syntaxin 4 dependent pyroptosis pathway

Aging, chronic high-fat diet feeding, or housing at thermoneutrality induces brown adipose tissue (BAT) involution, a process characterized by reduction of BAT mass and function with increased lipid droplet size. Single nuclei RNA sequencing of aged mice identifies a specific brown adipocyte population of Ucp1-low cells that are pyroptotic and display a reduction in the longevity gene syntaxin 4 (Stx4a). Similar to aged brown adipocytes, Ucp1-STX4KO mice display loss of brown adipose tissue mass and thermogenic dysfunction concomitant with increased pyroptosis. Restoration of STX4 expression or suppression of pyroptosis activation protects against the decline in both mass and thermogenic activity in the aged and Ucp1-STX4KO mice. Mechanistically, STX4 deficiency reduces oxidative phosphorylation, glucose uptake, and glycolysis leading to reduced ATP levels, a known triggering signal for pyroptosis. Together, these data demonstrate an understanding of rapid brown adipocyte involution and that physiologic aging and thermogenic dysfunction result from pyroptotic signaling activation.

Apoptosis and eryptosis: similarities and differences

Eryptosis is a regulated cell death (RCD) of mature erythrocytes initially described as a counterpart of apoptosis for enucleated cells. However, over the recent years, a growing number of studies have emphasized certain differences between both cell death modalities. In this review paper, we underline the hallmarks of eryptosis and apoptosis and highlight resemblances and dissimilarities between both RCDs. We summarize and critically discuss differences in the impact of caspase-3, Ca2+ signaling, ROS signaling pathways, opposing roles of casein kinase 1α, protein kinase C, Janus kinase 3, cyclin-dependent kinase 4, and AMP-activated protein kinase to highlight a certain degree of divergence between apoptosis and eryptosis. This review emphasizes the crucial importance of further studies that focus on deepening our knowledge of cell death machinery and identifying novel differences between cell death of nucleated and enucleated cells. This might provide evidence that erythrocytes can be defined as viable entities capable of programmed cell destruction. Additionally, the revealed cell type-specific patterns in cell death can facilitate the development of cell death-modulating therapeutic agents.

M6A methylation of FKFB3 reduced pyroptosis of gastric cancer by NLRP3

Gastric cancer is a kind of malignant tumor that seriously endangers human life and health. Its incidence rate and mortality rate are among the highest in the global malignant tumors. Therefore, this study explored the role of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) in the progression of gastric cancer and its underlying mechanism. Patients with gastric cancer were collected, and human GC cell lines (stomach gastric carcinoma 7901, stomach gastric carcinoma 823 , human gastric carcinoma cell line 803 and adenocarcinoma gastric stomach) were used in this study. We utilized glucose consumption, cell migration, and ELISA assay kits to investigate the function of GC. To understand its mechanism, we employed quantitative PCR (qPCR), western blot, and m6A methylated RNA immunoprecipitation assay. FKFB3 protein expression levels in patients with gastric cancer were increased. The induction of PFKFB3 mRNA expression levels in patients with gastric cancer or gastric cancer cell lines. Gastric cancer patients with high PFKFB3 expression had a lower survival rate. PFKFB3 high expression possessed the probability of pathological stage, lymph node metastasis or distant metastasis in patients with gastric cancer. PFKFB3 upregulation promoted cancer progression and Warburg effect progression of gastric cancer. PFKFB3 upregulation reduced pyroptosis and suppressed nucleotidebinding domain, leucinerich repeat containing protein 3-induced pyroptosis of gastric cancer. M6A-forming enzyme methyltransferase-like 3 increased PFKFB3 stability. Taken together, the M6A-forming enzyme methyltransferase-like 3 increased PFKFB3 stability and reduced pyroptosis in the model of gastric cancer through the Warburg effect. The PFKFB3 gene represents a potential therapeutic strategy for the treatment of gastric cancer.

Disulfidptosis: disulfide stress-induced cell death

The cystine transporter solute carrier family 7 member 11 (SLC7A11) (also known as xCT) promotes glutathione synthesis and counters oxidative stress-induced cell death, including ferroptosis, by importing cystine. Also, SLC7A11 plays a crucial role in tumor development. However, recent studies have uncovered an unexpected role of SLC7A11 in promoting disulfidptosis, a novel form of regulated cell death induced by disulfide stress. In this review, we examine the opposing roles of SLC7A11 in regulating redox homeostasis and cell survival/death, summarize current knowledge on disulfidptosis, and explore its potential in disease treatment. A deeper understanding of disulfidptosis will offer new insights into fundamental cellular homeostasis and facilitate the development of innovative therapies for disease treatment.

Inflammatory Consequences: Hepatitis C Virus-Induced Inflammasome Activation and Pyroptosis

Hepatitis C virus (HCV), despite the availability of effective direct-acting antivirals (DAAs) that clear the virus from >95% of individuals treated, continues to cause significant health care burden due to disease progression that can lead to fibrosis, cirrhosis, and/or hepatocellular carcinoma. The fact that some people who are treated with DAAs still go on to develop worsening liver disease warrants further study into the immunopathogenesis of HCV. Many viral infections, including HCV, have been associated with activation of the inflammasome/pyroptosis pathway. This inflammatory cell death pathway ultimately results in cell lysis and release of inflammatory cytokines, IL-18 and IL-1β. This review will report on studies that investigated HCV and inflammasome activation/pyroptosis. This includes clinical in vivo data showing elevated pyroptosis-associated cytokines in the blood of individuals living with HCV, studies of genetic associations of pyroptosis-related genes and development of liver disease, and in vitro studies aimed at understanding the mechanism of pyroptosis induced by HCV. Finally, we discuss major gaps in understanding and outstanding questions that remain in the field of HCV-induced pyroptosis.